What is water polarity?

The unequal sharing of electrons in a water molecule, giving oxygen a partial negative charge and the hydrogens partial positive charges.

What is a hydrogen bond?

A weak attraction between a partially positive hydrogen atom and a partially negative atom in another molecule.

Attraction between molecules of the same substance.

Attraction between molecules of different substances.

A liquid that dissolves solutes to form a solution.

What is specific heat capacity?

The energy required to raise the temperature of a unit mass of a substance by one degree.

What is latent heat of vaporization?

The energy required to vaporize a specified amount of liquid without changing its temperature.

Why does ice float on liquid water?

Hydrogen bonds hold water molecules in an open lattice in ice, making ice less dense than liquid water.

Which property of water makes sweating an effective cooling mechanism?

Water absorbs substantial energy as it evaporates; the highest-energy molecules leave, carrying heat away from the skin.

Why does water resist rapid temperature change?

Many hydrogen bonds must absorb energy before molecular motion increases substantially, giving water a high specific heat capacity.

How do cohesion and adhesion support water transport in narrow tubes?

Cohesion keeps water molecules connected, while adhesion helps the water column cling to the tube wall.

How does water participate differently in hydrolysis and condensation?

Hydrolysis consumes water to split a bond; condensation forms a bond and releases water.

How does floating ice protect aquatic life in winter?

Surface ice insulates the liquid water below, slowing further heat loss and preventing the whole body of water from freezing rapidly.

Why is water effective for transporting many biological solutes?

Its polarity allows ions and other polar molecules to become surrounded and dispersed in solution.

Why do nonpolar substances tend to cluster in water?

Clustering reduces the nonpolar surface exposed to water, allowing more water molecules to maintain hydrogen-bond interactions.

What is a nucleotide?

A nucleic-acid monomer made of a pentose sugar, a phosphate group, and a nitrogenous base.

What is a nucleoside?

A nitrogenous base joined to a pentose sugar, without a phosphate group.

What is a phosphodiester bond?

A covalent bond linking the phosphate of one nucleotide to the sugar of the next nucleotide.

A usually double-stranded nucleic acid that stores hereditary information in its base sequence.

A usually single-stranded nucleic acid involved in expressing and regulating genetic information.

What are antiparallel DNA strands?

Two DNA strands that run in opposite 5′ to 3′ directions.

What is complementary base pairing?

Specific pairing in which adenine pairs with thymine in DNA, or uracil in RNA, and cytosine pairs with guanine.

A nitrogenous base with two fused rings; adenine and guanine are purines.

What is a pyrimidine?

A nitrogenous base with one ring; cytosine, thymine, and uracil are pyrimidines.

The complete genetic material of an organism or cell.

What three structural features commonly distinguish RNA from DNA?

RNA usually contains ribose, uses uracil instead of thymine, and is single-stranded rather than double-stranded.

What determines the base sequence of the second DNA strand?

Complementary base-pairing rules determine it: A pairs with T, and C pairs with G.

What do the 5′ and 3′ labels of a nucleic-acid strand refer to?

They refer to numbered carbon atoms in the pentose sugar and define the strand's chemical direction.

Where is genetic information encoded in DNA?

In the order of nitrogenous bases along the DNA strand.

Why is ATP classified as a nucleotide?

It contains adenine, ribose, and phosphate groups, the three component types of a nucleotide.

How do mRNA, tRNA, and rRNA contribute to protein synthesis?

mRNA carries the coding sequence, tRNA delivers amino acids, and rRNA forms the catalytic and structural core of ribosomes.

How are a gene and a chromosome related?

A gene is a DNA sequence with a biological function; a chromosome is one long DNA molecule containing many genes and other sequences.

What happens to double-stranded DNA when it is denatured by heat?

Hydrogen bonds between complementary bases break and the two strands separate; the covalent backbones usually remain intact.

Why can each DNA strand serve as a template during replication?

Its base sequence determines a complementary sequence through specific base pairing.

IB Biology SL Flashcards: Complete Course Review

Review the current IB Biology Standard Level course with 960 independently written active-recall cards covering all 34 SL topics across molecules, cells, organisms, genetics, evolution, and ecology.

Автор Open Study Contributor

Об этой колоде

Study the current IB Biology SL course with 960 independently written English flashcards. The deck covers all 34 Standard Level topics through four broad groups: molecules and cells; metabolism and genetics; organisms and systems; and evolution and ecology.

Cards move from essential terms and structures to functions, mechanisms, comparisons, predictions, and compact interpretation prompts. Useful two-way term cards are separated by at least three unrelated cards, while explanatory answers are kept in the direction that supports meaningful recall. Every card carries the root tag ib-bio-sl and exactly one broad group tag.

The order introduces prerequisite ideas before dependent ones and progresses from simpler recall to more demanding reasoning within each topic. The deck is designed for ongoing spaced review. It does not replace data-heavy practice papers, extended-response practice, laboratory work, or the scientific investigation.

Reviewed in 2026 against the current Biology Standard Level course, first assessed in 2025.

Independent, unofficial study aid based on common biological knowledge. Not affiliated with or endorsed by the International Baccalaureate Organization. No copied IB examination questions, mark schemes, or curriculum text are included.

Check the official IB Biology course page for authoritative requirements.

Карточки в этой колоде

Карточка 1
Вопрос
What is water polarity?
Ответ
The unequal sharing of electrons in a water molecule, giving oxygen a partial negative charge and the hydrogens partial positive charges.
Карточка 2
Вопрос
What is a hydrogen bond?
Ответ
A weak attraction between a partially positive hydrogen atom and a partially negative atom in another molecule.
Карточка 3
Вопрос
What is cohesion?
Ответ
Attraction between molecules of the same substance.
Карточка 4
Вопрос
What is adhesion?
Ответ
Attraction between molecules of different substances.
Карточка 5
Вопрос
Which term describes unequal charge distribution within a water molecule?
Ответ
water polarity
Карточка 6
Вопрос
Which term describes the intermolecular attraction that links neighboring water molecules?
Ответ
a hydrogen bond
Карточка 7
Вопрос
Which term describes attraction between molecules of the same substance?
Ответ
cohesion
Карточка 8
Вопрос
Which term describes attraction between water and a different material?
Ответ
adhesion
Карточка 9
Вопрос
What is a solvent?
Ответ
A liquid that dissolves solutes to form a solution.
Карточка 10
Вопрос
What is specific heat capacity?
Ответ
The energy required to raise the temperature of a unit mass of a substance by one degree.
Карточка 11
Вопрос
What is latent heat of vaporization?
Ответ
The energy required to vaporize a specified amount of liquid without changing its temperature.
Карточка 12
Вопрос
Why does ice float on liquid water?
Ответ
Hydrogen bonds hold water molecules in an open lattice in ice, making ice less dense than liquid water.
Карточка 13
Вопрос
Which term describes a liquid that dissolves solutes?
Ответ
a solvent
Карточка 14
Вопрос
Which term describes the energy needed to raise a unit mass by one degree?
Ответ
specific heat capacity
Карточка 15
Вопрос
Which term describes the energy needed to vaporize a liquid without a temperature change?
Ответ
latent heat of vaporization
Карточка 16
Вопрос
Which property of water makes sweating an effective cooling mechanism?
Ответ
Water absorbs substantial energy as it evaporates; the highest-energy molecules leave, carrying heat away from the skin.
Карточка 17
Вопрос
Why does water resist rapid temperature change?
Ответ
Many hydrogen bonds must absorb energy before molecular motion increases substantially, giving water a high specific heat capacity.
Карточка 18
Вопрос
How do cohesion and adhesion support water transport in narrow tubes?
Ответ
Cohesion keeps water molecules connected, while adhesion helps the water column cling to the tube wall.
Карточка 19
Вопрос
How does water participate differently in hydrolysis and condensation?
Ответ
Hydrolysis consumes water to split a bond; condensation forms a bond and releases water.
Карточка 20
Вопрос
How does floating ice protect aquatic life in winter?
Ответ
Surface ice insulates the liquid water below, slowing further heat loss and preventing the whole body of water from freezing rapidly.
Карточка 21
Вопрос
Why is water effective for transporting many biological solutes?
Ответ
Its polarity allows ions and other polar molecules to become surrounded and dispersed in solution.
Карточка 22
Вопрос
Why do nonpolar substances tend to cluster in water?
Ответ
Clustering reduces the nonpolar surface exposed to water, allowing more water molecules to maintain hydrogen-bond interactions.
Карточка 23
Вопрос
What is a nucleotide?
Ответ
A nucleic-acid monomer made of a pentose sugar, a phosphate group, and a nitrogenous base.
Карточка 24
Вопрос
What is a nucleoside?
Ответ
A nitrogenous base joined to a pentose sugar, without a phosphate group.
Карточка 25
Вопрос
What is a phosphodiester bond?
Ответ
A covalent bond linking the phosphate of one nucleotide to the sugar of the next nucleotide.
Карточка 26
Вопрос
What is DNA?
Ответ
A usually double-stranded nucleic acid that stores hereditary information in its base sequence.
Карточка 27
Вопрос
Which term describes a sugar-phosphate-base monomer?
Ответ
a nucleotide
Карточка 28
Вопрос
Which term describes a base joined to a sugar but no phosphate?
Ответ
a nucleoside
Карточка 29
Вопрос
Which term describes the covalent linkage in a nucleic-acid sugar-phosphate backbone?
Ответ
a phosphodiester bond
Карточка 30
Вопрос
Which term describes the nucleic acid that usually stores hereditary information?
Ответ
DNA
Карточка 31
Вопрос
What is RNA?
Ответ
A usually single-stranded nucleic acid involved in expressing and regulating genetic information.
Карточка 32
Вопрос
What are antiparallel DNA strands?
Ответ
Two DNA strands that run in opposite 5′ to 3′ directions.
Карточка 33
Вопрос
What is complementary base pairing?
Ответ
Specific pairing in which adenine pairs with thymine in DNA, or uracil in RNA, and cytosine pairs with guanine.
Карточка 34
Вопрос
What is a purine?
Ответ
A nitrogenous base with two fused rings; adenine and guanine are purines.
Карточка 35
Вопрос
Which term describes the usually single-stranded nucleic acid used in gene expression?
Ответ
RNA
Карточка 36
Вопрос
Which term describes DNA strands running in opposite directions?
Ответ
antiparallel DNA strands
Карточка 37
Вопрос
Which term describes specific A–T or A–U and C–G pairing?
Ответ
complementary base pairing
Карточка 38
Вопрос
Which term describes a two-ring nitrogenous base?
Ответ
a purine
Карточка 39
Вопрос
What is a pyrimidine?
Ответ
A nitrogenous base with one ring; cytosine, thymine, and uracil are pyrimidines.
Карточка 40
Вопрос
What is a genome?
Ответ
The complete genetic material of an organism or cell.
Карточка 41
Вопрос
What three structural features commonly distinguish RNA from DNA?
Ответ
RNA usually contains ribose, uses uracil instead of thymine, and is single-stranded rather than double-stranded.
Карточка 42
Вопрос
What determines the base sequence of the second DNA strand?
Ответ
Complementary base-pairing rules determine it: A pairs with T, and C pairs with G.
Карточка 43
Вопрос
Which term describes a one-ring nitrogenous base?
Ответ
a pyrimidine
Карточка 44
Вопрос
Which term describes the complete genetic material of an organism?
Ответ
a genome
Карточка 45
Вопрос
What do the 5′ and 3′ labels of a nucleic-acid strand refer to?
Ответ
They refer to numbered carbon atoms in the pentose sugar and define the strand's chemical direction.
Карточка 46
Вопрос
Where is genetic information encoded in DNA?
Ответ
In the order of nitrogenous bases along the DNA strand.
Карточка 47
Вопрос
Why is ATP classified as a nucleotide?
Ответ
It contains adenine, ribose, and phosphate groups, the three component types of a nucleotide.
Карточка 48
Вопрос
How do mRNA, tRNA, and rRNA contribute to protein synthesis?
Ответ
mRNA carries the coding sequence, tRNA delivers amino acids, and rRNA forms the catalytic and structural core of ribosomes.
Карточка 49
Вопрос
How are a gene and a chromosome related?
Ответ
A gene is a DNA sequence with a biological function; a chromosome is one long DNA molecule containing many genes and other sequences.
Карточка 50
Вопрос
What happens to double-stranded DNA when it is denatured by heat?
Ответ
Hydrogen bonds between complementary bases break and the two strands separate; the covalent backbones usually remain intact.
Карточка 51
Вопрос
Why can each DNA strand serve as a template during replication?
Ответ
Its base sequence determines a complementary sequence through specific base pairing.
Карточка 52
Вопрос
In which direction are new nucleic-acid strands synthesized?
Ответ
Nucleotides are added to the 3′ end, so synthesis proceeds 5′ to 3′.
Карточка 53
Вопрос
What is a monosaccharide?
Ответ
A single sugar unit that can serve as a carbohydrate monomer.
Карточка 54
Вопрос
What is a disaccharide?
Ответ
A carbohydrate formed from two monosaccharides joined by a glycosidic bond.
Карточка 55
Вопрос
What is a polysaccharide?
Ответ
A polymer made from many monosaccharide units.
Карточка 56
Вопрос
What is a glycosidic bond?
Ответ
A covalent bond joining monosaccharides in a carbohydrate.
Карточка 57
Вопрос
Which term describes a single sugar unit?
Ответ
a monosaccharide
Карточка 58
Вопрос
Which term describes two monosaccharides joined together?
Ответ
a disaccharide
Карточка 59
Вопрос
Which term describes a polymer of many sugar units?
Ответ
a polysaccharide
Карточка 60
Вопрос
Which term describes the covalent linkage between monosaccharides?
Ответ
a glycosidic bond
Карточка 61
Вопрос
What is a triglyceride?
Ответ
A lipid formed from glycerol joined to three fatty acids.
Карточка 62
Вопрос
What is a fatty acid?
Ответ
A hydrocarbon chain with a carboxyl group that can form part of many lipids.
Карточка 63
Вопрос
What is a saturated fatty acid?
Ответ
A fatty acid with no carbon-carbon double bonds in its hydrocarbon chain.
Карточка 64
Вопрос
What is a phospholipid?
Ответ
An amphipathic lipid with a phosphate-containing hydrophilic head and hydrophobic fatty-acid tails.
Карточка 65
Вопрос
Which term describes glycerol joined to three fatty acids?
Ответ
a triglyceride
Карточка 66
Вопрос
Which term describes a hydrocarbon chain ending in a carboxyl group?
Ответ
a fatty acid
Карточка 67
Вопрос
Which term describes a fatty acid without carbon-carbon double bonds?
Ответ
a saturated fatty acid
Карточка 68
Вопрос
Which term describes a lipid with a polar head and nonpolar tails?
Ответ
a phospholipid
Карточка 69
Вопрос
How is a glycosidic bond formed between two monosaccharides?
Ответ
A condensation reaction joins them and releases a molecule of water.
Карточка 70
Вопрос
How is a polysaccharide broken into smaller sugars?
Ответ
Hydrolysis adds water across glycosidic bonds, splitting the polymer.
Карточка 71
Вопрос
Which polysaccharides store glucose in plants and animals?
Ответ
Starch stores glucose in plants; glycogen stores glucose in animals and fungi.
Карточка 72
Вопрос
Why is cellulose suitable for plant cell walls?
Ответ
Its straight β-glucose chains hydrogen-bond into strong microfibrils that resist stretching.
Карточка 73
Вопрос
Why do lipids store more energy per gram than carbohydrates?
Ответ
Lipids contain more energy-rich carbon-hydrogen bonds and are more reduced.
Карточка 74
Вопрос
Why do phospholipids form bilayers in water?
Ответ
Hydrophilic heads interact with water while hydrophobic tails cluster away from water.
Карточка 75
Вопрос
Besides energy storage, what are three biological roles of lipids?
Ответ
They form membranes, provide thermal insulation and cushioning, and can act as signaling molecules.
Карточка 76
Вопрос
How do cis double bonds affect fatty-acid packing and melting point?
Ответ
They introduce bends that reduce close packing, usually lowering the melting point.
Карточка 77
Вопрос
What is an amino acid?
Ответ
A protein monomer with an amino group, a carboxyl group, a hydrogen, and a variable R group attached to a central carbon.
Карточка 78
Вопрос
What is a peptide bond?
Ответ
The covalent bond formed between the amino group of one amino acid and the carboxyl group of another.
Карточка 79
Вопрос
What is a polypeptide?
Ответ
A chain of amino acids joined by peptide bonds.
Карточка 80
Вопрос
What is protein primary structure?
Ответ
The amino-acid sequence of a polypeptide.
Карточка 81
Вопрос
Which term describes a protein monomer with amino, carboxyl, and variable R groups?
Ответ
an amino acid
Карточка 82
Вопрос
Which term describes the covalent linkage between amino acids?
Ответ
a peptide bond
Карточка 83
Вопрос
Which term describes a chain of peptide-linked amino acids?
Ответ
a polypeptide
Карточка 84
Вопрос
Which term describes a protein's amino-acid sequence?
Ответ
protein primary structure
Карточка 85
Вопрос
What is protein secondary structure?
Ответ
Local folding such as α-helices and β-sheets stabilized mainly by backbone hydrogen bonds.
Карточка 86
Вопрос
What is protein tertiary structure?
Ответ
The overall three-dimensional shape of one polypeptide produced by interactions among R groups and the backbone.
Карточка 87
Вопрос
What is protein quaternary structure?
Ответ
The arrangement of multiple polypeptide subunits in one functional protein.
Карточка 88
Вопрос
What is protein denaturation?
Ответ
Loss of a protein's normal three-dimensional shape and therefore usually its function.
Карточка 89
Вопрос
Which term describes local α-helix and β-sheet folding?
Ответ
protein secondary structure
Карточка 90
Вопрос
Which term describes the overall three-dimensional shape of one polypeptide?
Ответ
protein tertiary structure
Карточка 91
Вопрос
Which term describes the association of multiple polypeptide subunits?
Ответ
protein quaternary structure
Карточка 92
Вопрос
Which term describes loss of a protein's native shape?
Ответ
protein denaturation
Карточка 93
Вопрос
What mainly gives different amino acids their different chemical properties?
Ответ
Their variable R groups.
Карточка 94
Вопрос
What reaction forms a peptide bond?
Ответ
A condensation reaction releases water as the amino and carboxyl groups join.
Карточка 95
Вопрос
Why can high temperature denature a protein?
Ответ
Increased molecular motion disrupts weak interactions that maintain the protein's shape.
Карточка 96
Вопрос
Why can extreme pH denature a protein?
Ответ
It changes the charges of R groups and disrupts ionic and hydrogen-bond interactions.
Карточка 97
Вопрос
How do fibrous and globular proteins generally differ?
Ответ
Fibrous proteins are elongated and mainly structural; globular proteins are compact and often perform dynamic functions.
Карточка 98
Вопрос
Why is three-dimensional shape crucial to protein function?
Ответ
It creates specific binding, catalytic, structural, or interaction surfaces.
Карточка 99
Вопрос
Name four broad biological roles of proteins.
Ответ
Catalysis, transport, signaling, defense, movement, and structural support are major roles; any four are sufficient.
Карточка 100
Вопрос
How can changing one amino acid alter protein function?
Ответ
The substitution can change R-group interactions, folding, stability, or an active or binding site.
Карточка 101
Вопрос
What is cell theory?
Ответ
The principles that living organisms are made of cells, cells are the basic units of life, and cells arise from pre-existing cells.
Карточка 102
Вопрос
What is a prokaryotic cell?
Ответ
A cell without a nucleus or other membrane-bound organelles.
Карточка 103
Вопрос
What is a eukaryotic cell?
Ответ
A cell with DNA enclosed in a nucleus and with membrane-bound organelles.
Карточка 104
Вопрос
What is the nucleus?
Ответ
The double-membrane organelle that contains most of a eukaryotic cell's DNA.
Карточка 105
Вопрос
Which term describes the principles describing cells as life's basic units?
Ответ
cell theory
Карточка 106
Вопрос
Which term describes a cell lacking a nucleus and membrane-bound organelles?
Ответ
a prokaryotic cell
Карточка 107
Вопрос
Which term describes a cell with a nucleus and membrane-bound organelles?
Ответ
a eukaryotic cell
Карточка 108
Вопрос
Which term describes the organelle containing most eukaryotic DNA?
Ответ
the nucleus
Карточка 109
Вопрос
What is a ribosome?
Ответ
A molecular complex of rRNA and proteins that synthesizes polypeptides.
Карточка 110
Вопрос
What is the cytoplasm?
Ответ
The material inside the plasma membrane but outside the nucleus, including cytosol and organelles.
Карточка 111
Вопрос
What is the plasma membrane?
Ответ
The selectively permeable boundary separating a cell from its environment.
Карточка 112
Вопрос
What is a cell wall?
Ответ
A rigid extracellular layer that supports and protects cells in plants, fungi, and most prokaryotes.
Карточка 113
Вопрос
Which term describes the complex that synthesizes polypeptides?
Ответ
a ribosome
Карточка 114
Вопрос
Which term describes cell contents inside the plasma membrane but outside the nucleus?
Ответ
the cytoplasm
Карточка 115
Вопрос
Which term describes the selectively permeable cell boundary?
Ответ
the plasma membrane
Карточка 116
Вопрос
Which term describes a rigid extracellular support layer?
Ответ
a cell wall
Карточка 117
Вопрос
What is the nucleoid?
Ответ
The non-membrane-bound region containing the main chromosome of a prokaryotic cell.
Карточка 118
Вопрос
What is the cytoskeleton?
Ответ
A dynamic network of protein filaments involved in cell shape, transport, division, and movement.
Карточка 119
Вопрос
What structures are shared by all cells?
Ответ
A plasma membrane, cytoplasm, genetic material, and ribosomes.
Карточка 120
Вопрос
Which structures distinguish a typical plant cell from a typical animal cell?
Ответ
A plant cell has a cellulose wall, chloroplasts in photosynthetic tissues, and a large central vacuole; an animal cell lacks these.
Карточка 121
Вопрос
Which term describes the prokaryotic chromosome-containing region?
Ответ
the nucleoid
Карточка 122
Вопрос
Which term describes the internal network of protein filaments?
Ответ
the cytoskeleton
Карточка 123
Вопрос
How is genetic material commonly organized in a prokaryotic cell?
Ответ
The main DNA is usually one circular chromosome in the nucleoid, often accompanied by smaller plasmids.
Карточка 124
Вопрос
How is microscope magnification calculated?
Ответ
Magnification = image size ÷ actual size, using the same units.
Карточка 125
Вопрос
What does microscope resolution describe?
Ответ
The ability to distinguish two close points as separate.
Карточка 126
Вопрос
Arrange these from smallest to largest: ribosome, bacterium, animal cell.
Ответ
Ribosome, bacterium, animal cell.
Карточка 127
Вопрос
How does the cytoskeleton support intracellular transport?
Ответ
Motor proteins move vesicles and other cargo along cytoskeletal filaments.
Карточка 128
Вопрос
Why does a small cell usually exchange materials more efficiently than a geometrically similar large cell?
Ответ
It has a larger surface-area-to-volume ratio, providing more exchange surface per unit of cell contents.
Карточка 129
Вопрос
Why is a cell more than a collection of isolated molecules?
Ответ
Organized interactions among components produce emergent functions such as metabolism, regulation, and reproduction.
Карточка 130
Вопрос
What major advantage do membrane-bound organelles give eukaryotic cells?
Ответ
They separate incompatible reactions and create specialized local conditions.
Карточка 131
Вопрос
What is a phospholipid bilayer?
Ответ
A double layer of phospholipids with hydrophilic heads facing water and hydrophobic tails facing inward.
Карточка 132
Вопрос
What is the fluid mosaic model?
Ответ
A model describing membranes as mobile phospholipids containing a changing mosaic of proteins and other components.
Карточка 133
Вопрос
What is an integral membrane protein?
Ответ
A protein embedded in the bilayer, often spanning it.
Карточка 134
Вопрос
What is a peripheral membrane protein?
Ответ
A protein attached to a membrane surface rather than embedded in the bilayer.
Карточка 135
Вопрос
Which term describes a double phospholipid layer with inward-facing tails?
Ответ
a phospholipid bilayer
Карточка 136
Вопрос
Which term describes the model of a mobile lipid layer containing varied proteins?
Ответ
the fluid mosaic model
Карточка 137
Вопрос
Which term describes a protein embedded within the lipid bilayer?
Ответ
an integral membrane protein
Карточка 138
Вопрос
Which term describes a protein attached to a membrane surface?
Ответ
a peripheral membrane protein
Карточка 139
Вопрос
What is membrane cholesterol?
Ответ
An amphipathic lipid that buffers membrane fluidity and reduces permeability in animal cells.
Карточка 140
Вопрос
What is a glycoprotein?
Ответ
A protein with an attached carbohydrate chain, often used in recognition, adhesion, or signaling.
Карточка 141
Вопрос
What is diffusion?
Ответ
Net movement of particles from a region of higher concentration to lower concentration due to random motion.
Карточка 142
Вопрос
What is osmosis?
Ответ
Net movement of water across a selectively permeable membrane from higher water potential to lower water potential.
Карточка 143
Вопрос
Which term describes the animal-membrane lipid that buffers fluidity?
Ответ
membrane cholesterol
Карточка 144
Вопрос
Which term describes a carbohydrate-bearing protein?
Ответ
a glycoprotein
Карточка 145
Вопрос
Which term describes net movement down a concentration gradient?
Ответ
diffusion
Карточка 146
Вопрос
Which term describes net water movement across a selectively permeable membrane?
Ответ
osmosis
Карточка 147
Вопрос
What is facilitated diffusion?
Ответ
Passive movement down a gradient through a membrane channel or carrier protein.
Карточка 148
Вопрос
What is active transport?
Ответ
Energy-requiring movement of a substance against its concentration or electrochemical gradient.
Карточка 149
Вопрос
Why is the phospholipid bilayer selectively permeable?
Ответ
Its hydrophobic interior allows small nonpolar molecules through more readily than ions and most large or polar molecules.
Карточка 150
Вопрос
How do simple diffusion and facilitated diffusion differ?
Ответ
Both are passive, but facilitated diffusion uses specific membrane proteins while simple diffusion passes through the bilayer.
Карточка 151
Вопрос
Which term describes passive transport through a channel or carrier?
Ответ
facilitated diffusion
Карточка 152
Вопрос
Which term describes energy-dependent transport against a gradient?
Ответ
active transport
Карточка 153
Вопрос
How do channel and carrier proteins differ?
Ответ
Channels provide hydrophilic pores; carriers bind solutes and change shape to move them.
Карточка 154
Вопрос
How can an ATP-driven pump maintain an ion gradient?
Ответ
It couples ATP hydrolysis to a conformational change that moves ions against their electrochemical gradient.
Карточка 155
Вопрос
How does endocytosis move material into a cell?
Ответ
The plasma membrane folds inward and pinches off a vesicle containing the material.
Карточка 156
Вопрос
How does exocytosis move material out of a cell?
Ответ
An intracellular vesicle fuses with the plasma membrane and releases its contents outside.
Карточка 157
Вопрос
What happens to an animal cell in a strongly hypotonic solution?
Ответ
Water enters by osmosis; without a cell wall, the cell may swell and lyse.
Карточка 158
Вопрос
Does molecular movement stop when diffusion reaches equilibrium?
Ответ
No. Molecules continue moving randomly, but there is no net movement between regions.
Карточка 159
Вопрос
How does decreasing temperature generally affect membrane fluidity?
Ответ
It reduces phospholipid movement and makes the membrane less fluid.
Карточка 160
Вопрос
Why do unsaturated fatty-acid tails increase membrane fluidity?
Ответ
Their cis double-bond bends prevent phospholipids from packing tightly.
Карточка 161
Вопрос
What changes increase the rate of simple diffusion across a membrane?
Ответ
A steeper gradient, larger surface area, higher temperature, shorter distance, and greater membrane permeability increase the rate.
Карточка 162
Вопрос
What is a mitochondrion?
Ответ
A double-membrane organelle where most aerobic ATP production occurs.
Карточка 163
Вопрос
What is a chloroplast?
Ответ
A double-membrane organelle where photosynthesis occurs in plants and algae.
Карточка 164
Вопрос
What is rough endoplasmic reticulum?
Ответ
A membrane network bearing ribosomes that synthesizes and begins processing many secreted and membrane proteins.
Карточка 165
Вопрос
What is smooth endoplasmic reticulum?
Ответ
A membrane network involved in lipid synthesis, detoxification, and calcium storage.
Карточка 166
Вопрос
Which term describes the main organelle of aerobic ATP production?
Ответ
a mitochondrion
Карточка 167
Вопрос
Which term describes the photosynthetic organelle of plants and algae?
Ответ
a chloroplast
Карточка 168
Вопрос
Which term describes the ribosome-studded membrane network?
Ответ
rough endoplasmic reticulum
Карточка 169
Вопрос
Which term describes the membrane network that lacks ribosomes and synthesizes lipids?
Ответ
smooth endoplasmic reticulum
Карточка 170
Вопрос
What is the Golgi apparatus?
Ответ
Stacked membranes that modify, sort, and package proteins and lipids into vesicles.
Карточка 171
Вопрос
What is a lysosome?
Ответ
An acidic enzyme-containing organelle that digests macromolecules and worn cellular components.
Карточка 172
Вопрос
What is a vesicle?
Ответ
A small membrane-bound compartment used for transport, storage, or chemical reactions.
Карточка 173
Вопрос
What is the central vacuole?
Ответ
A large plant-cell compartment that stores solutes and helps maintain turgor pressure.
Карточка 174
Вопрос
Which term describes the organelle that modifies and sorts cellular cargo?
Ответ
the Golgi apparatus
Карточка 175
Вопрос
Which term describes the acidic digestive organelle?
Ответ
a lysosome
Карточка 176
Вопрос
Which term describes a small membrane-bound transport compartment?
Ответ
a vesicle
Карточка 177
Вопрос
Which term describes the large plant compartment that supports turgor?
Ответ
the central vacuole
Карточка 178
Вопрос
Why can compartmentalization increase metabolic efficiency?
Ответ
It concentrates enzymes and substrates, maintains suitable local conditions, and separates incompatible reactions.
Карточка 179
Вопрос
How do mitochondrial cristae support ATP production?
Ответ
They increase inner-membrane area for electron transport chains and ATP synthase.
Карточка 180
Вопрос
Why are chloroplast thylakoids arranged as extensive membranes?
Ответ
They provide a large surface for light-absorbing complexes, electron transport chains, and ATP synthase.
Карточка 181
Вопрос
What is the main function of the nucleolus?
Ответ
It produces rRNA and assembles ribosomal subunits.
Карточка 182
Вопрос
Trace a secreted protein from synthesis to release.
Ответ
Ribosome on rough ER → ER lumen → transport vesicle → Golgi apparatus → secretory vesicle → plasma membrane → exocytosis.
Карточка 183
Вопрос
Why does a lysosome maintain an acidic interior?
Ответ
Its hydrolytic enzymes work best at low pH, and acidity helps confine their activity from the cytosol.
Карточка 184
Вопрос
How do the nucleus, ribosomes, ER, and Golgi cooperate in protein production?
Ответ
DNA instructions are transcribed in the nucleus; ribosomes translate them; ER folds or modifies many products; Golgi further modifies and sorts them.
Карточка 185
Вопрос
How are transport vesicles directed to the correct target membrane?
Ответ
Specific recognition proteins on vesicles and target membranes interact, allowing selective docking and fusion.
Карточка 186
Вопрос
What is cell differentiation?
Ответ
The process by which a cell develops specialized structure and function.
Карточка 187
Вопрос
What is a stem cell?
Ответ
An unspecialized cell able to self-renew and produce differentiated cells.
Карточка 188
Вопрос
What is gene expression?
Ответ
Use of genetic information to produce a functional RNA or protein product.
Карточка 189
Вопрос
What is a tissue?
Ответ
A coordinated group of similar or related cells performing a shared function.
Карточка 190
Вопрос
Which term describes development of specialized cell structure and function?
Ответ
cell differentiation
Карточка 191
Вопрос
Which term describes an unspecialized self-renewing cell?
Ответ
a stem cell
Карточка 192
Вопрос
Which term describes production of a functional product from genetic information?
Ответ
gene expression
Карточка 193
Вопрос
Which term describes a group of coordinated cells with a shared function?
Ответ
a tissue
Карточка 194
Вопрос
What is an organ?
Ответ
A structure made of multiple tissues working together for particular functions.
Карточка 195
Вопрос
What is the organ-system level of biological organization?
Ответ
A group of organs that coordinate to perform major functions for an organism.
Карточка 196
Вопрос
What is surface-area-to-volume ratio?
Ответ
The amount of surface area available relative to the volume it must serve.
Карточка 197
Вопрос
How can two specialized cells have the same genome but different structures?
Ответ
They express different sets and amounts of genes, producing different proteins and cellular features.
Карточка 198
Вопрос
Which term describes a structure composed of multiple tissue types?
Ответ
an organ
Карточка 199
Вопрос
Which term describes the level of biological organization formed by coordinated organs?
Ответ
an organ system
Карточка 200
Вопрос
Which term describes surface area available per unit volume?
Ответ
surface-area-to-volume ratio
Карточка 201
Вопрос
How is a mammalian red blood cell specialized for oxygen transport?
Ответ
Its biconcave shape increases exchange area, it is flexible, and loss of its nucleus leaves more space for hemoglobin.
Карточка 202
Вопрос
How is a sperm cell specialized for fertilization?
Ответ
It has a flagellum for movement, many mitochondria for ATP, a haploid nucleus, and an acrosome containing enzymes.
Карточка 203
Вопрос
How is a neuron specialized for rapid communication?
Ответ
Long processes carry signals over distance, branching dendrites receive inputs, and synaptic terminals transmit signals to other cells.
Карточка 204
Вопрос
How is a root hair cell specialized for mineral and water uptake?
Ответ
Its long projection increases surface area, its thin wall shortens the pathway, and membrane transport proteins take up ions.
Карточка 205
Вопрос
How is a palisade mesophyll cell specialized for photosynthesis?
Ответ
It contains many chloroplasts and is positioned near the upper leaf surface where light is strongest.
Карточка 206
Вопрос
How do ciliated epithelial cells help protect airways?
Ответ
Their cilia move mucus containing trapped particles and microbes toward the throat.
Карточка 207
Вопрос
Why can extreme specialization reduce a cell's independence?
Ответ
Resources and structures are committed to a narrow role, so the cell depends on other cells for functions it no longer performs well.
Карточка 208
Вопрос
What is water potential?
Ответ
The potential energy of water per unit volume relative to pure water, used to predict the direction of water movement.
Карточка 209
Вопрос
What is solute potential?
Ответ
The negative contribution of dissolved solutes to water potential.
Карточка 210
Вопрос
What is pressure potential?
Ответ
The contribution of physical pressure to water potential.
Карточка 211
Вопрос
What is turgor pressure?
Ответ
Outward pressure of a plant-cell interior against its cell wall after water uptake.
Карточка 212
Вопрос
Which term describes the tendency of water to move relative to pure water?
Ответ
water potential
Карточка 213
Вопрос
Which term describes the water-potential component lowered by dissolved solutes?
Ответ
solute potential
Карточка 214
Вопрос
Which term describes the water-potential component caused by physical pressure?
Ответ
pressure potential
Карточка 215
Вопрос
Which term describes pressure of plant-cell contents against the wall?
Ответ
turgor pressure
Карточка 216
Вопрос
What is plasmolysis?
Ответ
Separation of the plasma membrane from the cell wall after a plant cell loses water.
Карточка 217
Вопрос
What is a flaccid plant cell?
Ответ
A plant cell with insufficient turgor pressure to be firm.
Карточка 218
Вопрос
What is an isotonic condition?
Ответ
A condition in which two solutions have equal effective water potential and no net water movement occurs.
Карточка 219
Вопрос
In which direction does water move across a permeable membrane?
Ответ
From higher water potential to lower water potential.
Карточка 220
Вопрос
Which term describes membrane separation from the plant cell wall after water loss?
Ответ
plasmolysis
Карточка 221
Вопрос
Which term describes a plant cell lacking firm turgor?
Ответ
a flaccid plant cell
Карточка 222
Вопрос
Which term describes equal effective water potential across a membrane?
Ответ
an isotonic condition
Карточка 223
Вопрос
What is the water potential of pure water at standard pressure?
Ответ
Zero; adding solute makes water potential more negative.
Карточка 224
Вопрос
How are water potential, solute potential, and pressure potential related?
Ответ
Water potential equals solute potential plus pressure potential: Ψ = Ψs + Ψp.
Карточка 225
Вопрос
Why does a plant cell usually become turgid rather than burst in a hypotonic solution?
Ответ
Water entry raises pressure potential, while the rigid cell wall resists further expansion.
Карточка 226
Вопрос
What happens to a plant cell placed in a solution with much lower water potential?
Ответ
Water leaves the cell, turgor falls, and severe loss can cause plasmolysis.
Карточка 227
Вопрос
Can two solutions have different solute concentrations but equal water potential?
Ответ
Yes. A difference in pressure potential can offset a difference in solute potential.
Карточка 228
Вопрос
What is an enzyme?
Ответ
A biological catalyst that increases reaction rate without being consumed.
Карточка 229
Вопрос
What is an active site?
Ответ
The region of an enzyme where substrate binds and catalysis occurs.
Карточка 230
Вопрос
What is a substrate?
Ответ
A reactant molecule on which an enzyme acts.
Карточка 231
Вопрос
What is activation energy?
Ответ
The minimum energy input needed for a reaction to begin.
Карточка 232
Вопрос
Which term describes a biological catalyst?
Ответ
an enzyme
Карточка 233
Вопрос
Which term describes the substrate-binding catalytic region of an enzyme?
Ответ
an active site
Карточка 234
Вопрос
Which term describes a reactant bound and changed by an enzyme?
Ответ
a substrate
Карточка 235
Вопрос
Which term describes the energy barrier that must be overcome for a reaction?
Ответ
activation energy
Карточка 236
Вопрос
What is the induced-fit model?
Ответ
The model in which substrate binding changes active-site shape to improve catalytic interactions.
Карточка 237
Вопрос
What is enzyme denaturation?
Ответ
Loss of the active three-dimensional shape of an enzyme, usually causing loss of activity.
Карточка 238
Вопрос
What is competitive inhibition?
Ответ
Inhibition caused by a molecule competing with substrate for the active site.
Карточка 239
Вопрос
What is noncompetitive inhibition?
Ответ
Inhibition caused by binding away from the active site and reducing catalytic function.
Карточка 240
Вопрос
Which term describes the model where substrate binding reshapes the active site?
Ответ
the induced-fit model
Карточка 241
Вопрос
Which term describes loss of an enzyme's functional shape?
Ответ
enzyme denaturation
Карточка 242
Вопрос
Which term describes inhibition by active-site competition?
Ответ
competitive inhibition
Карточка 243
Вопрос
Which term describes inhibition by binding outside the active site?
Ответ
noncompetitive inhibition
Карточка 244
Вопрос
What is an enzyme optimum?
Ответ
The condition, such as temperature or pH, at which an enzyme's activity is highest.
Карточка 245
Вопрос
What is feedback inhibition?
Ответ
Control in which a pathway product inhibits an enzyme acting earlier in the pathway.
Карточка 246
Вопрос
How does an enzyme increase reaction rate?
Ответ
It stabilizes the transition state and provides a pathway with lower activation energy.
Карточка 247
Вопрос
Why does enzyme activity often rise and then fall as temperature increases?
Ответ
Molecular collisions initially increase, but excessive heat disrupts enzyme shape and denatures the active site.
Карточка 248
Вопрос
Which term describes the condition producing maximum enzyme activity?
Ответ
an enzyme optimum
Карточка 249
Вопрос
Which term describes pathway control by inhibition from an end product?
Ответ
feedback inhibition
Карточка 250
Вопрос
Why does each enzyme have a characteristic pH range?
Ответ
pH changes the ionization of amino-acid side chains, affecting active-site shape and chemical interactions.
Карточка 251
Вопрос
Why does increasing substrate concentration eventually stop increasing enzyme rate?
Ответ
At saturation, nearly all active sites are occupied and enzyme concentration limits the maximum rate.
Карточка 252
Вопрос
How does increasing enzyme concentration affect rate when substrate is abundant?
Ответ
More active sites are available, so the initial rate increases roughly in proportion to enzyme concentration.
Карточка 253
Вопрос
What gives an enzyme substrate specificity?
Ответ
The active site's shape, charge, polarity, and chemical groups complement particular substrates and transition states.
Карточка 254
Вопрос
What is one practical advantage of immobilizing an enzyme?
Ответ
The enzyme can be separated from products and reused while conditions around it are controlled.
Карточка 255
Вопрос
Does an enzyme change a reaction's equilibrium position?
Ответ
No. It speeds forward and reverse reactions but does not change the equilibrium constant or final equilibrium position.
Карточка 256
Вопрос
How can high substrate concentration reduce competitive inhibition?
Ответ
More substrate molecules increase the chance that substrate rather than inhibitor occupies the active site.
Карточка 257
Вопрос
Why are metabolic reactions commonly organized into pathways?
Ответ
A sequence of enzyme-controlled steps allows energy changes and intermediates to be controlled and coupled.
Карточка 258
Вопрос
What is ATP?
Ответ
A nucleotide that transfers usable energy through coupling of its hydrolysis to cellular processes.
Карточка 259
Вопрос
What is cellular respiration?
Ответ
Controlled release of energy from organic molecules to produce ATP.
Карточка 260
Вопрос
What is glycolysis?
Ответ
A cytosolic pathway that splits glucose into two pyruvate molecules and yields a small amount of ATP and reduced electron carriers.
Карточка 261
Вопрос
What is pyruvate?
Ответ
The three-carbon product of glycolysis that can enter aerobic or anaerobic pathways.
Карточка 262
Вопрос
Which term describes the cell's immediate phosphoryl-group energy carrier?
Ответ
ATP
Карточка 263
Вопрос
Which term describes controlled ATP-producing breakdown of organic molecules?
Ответ
cellular respiration
Карточка 264
Вопрос
Which term describes the cytosolic splitting of glucose into pyruvate?
Ответ
glycolysis
Карточка 265
Вопрос
Which term describes the three-carbon product of glycolysis?
Ответ
pyruvate
Карточка 266
Вопрос
What is aerobic respiration?
Ответ
Respiration that uses oxygen as the final electron acceptor and produces much more ATP than fermentation.
Карточка 267
Вопрос
What is anaerobic metabolism?
Ответ
ATP-producing metabolism that proceeds without oxygen.
Карточка 268
Вопрос
What is fermentation?
Ответ
An anaerobic pathway that regenerates oxidized electron carriers so glycolysis can continue.
Карточка 269
Вопрос
What is oxidation?
Ответ
Loss of electrons, often accompanied in biology by loss of hydrogen or gain of oxygen.
Карточка 270
Вопрос
Which term describes respiration using oxygen as final electron acceptor?
Ответ
aerobic respiration
Карточка 271
Вопрос
Which term describes ATP-producing metabolism without oxygen?
Ответ
anaerobic metabolism
Карточка 272
Вопрос
Which term describes anaerobic regeneration of electron carriers after glycolysis?
Ответ
fermentation
Карточка 273
Вопрос
Which term describes loss of electrons?
Ответ
oxidation
Карточка 274
Вопрос
What is reduction?
Ответ
Gain of electrons, often accompanied in biology by gain of hydrogen or loss of oxygen.
Карточка 275
Вопрос
What is a reduced electron carrier?
Ответ
A molecule such as NADH that carries high-energy electrons and hydrogen from one reaction to another.
Карточка 276
Вопрос
What is chemiosmosis?
Ответ
ATP production driven by ions moving down an electrochemical gradient through ATP synthase.
Карточка 277
Вопрос
What is the overall word equation for aerobic respiration of glucose?
Ответ
Glucose + oxygen → carbon dioxide + water + energy transferred to ATP and heat.
Карточка 278
Вопрос
Which term describes gain of electrons?
Ответ
reduction
Карточка 279
Вопрос
Which term describes a molecule carrying high-energy electrons between reactions?
Ответ
a reduced electron carrier
Карточка 280
Вопрос
Which term describes ATP production powered by an ion gradient?
Ответ
chemiosmosis
Карточка 281
Вопрос
Where does glycolysis occur?
Ответ
In the cytosol.
Карточка 282
Вопрос
What major stages of aerobic respiration occur in mitochondria?
Ответ
Pyruvate oxidation and the citric acid cycle occur in the matrix; electron transport and chemiosmosis occur at the inner membrane.
Карточка 283
Вопрос
What is oxygen's direct role in aerobic respiration?
Ответ
It accepts electrons and hydrogen ions at the end of the electron transport chain, forming water.
Карточка 284
Вопрос
Why does aerobic respiration yield much more ATP per glucose than fermentation?
Ответ
It transfers electrons through an electron transport chain and uses oxidative phosphorylation, extracting far more of glucose's energy.
Карточка 285
Вопрос
What is the purpose of lactate formation in oxygen-limited animal cells?
Ответ
It regenerates NAD⁺ so glycolysis can continue producing a small amount of ATP.
Карточка 286
Вопрос
What products are formed during alcoholic fermentation in yeast?
Ответ
Ethanol and carbon dioxide, while NAD⁺ is regenerated.
Карточка 287
Вопрос
Why is some energy released by respiration transferred as heat rather than captured in ATP?
Ответ
Energy conversions are not fully efficient, so part of the chemical energy becomes disordered molecular motion.
Карточка 288
Вопрос
What is substrate-level phosphorylation?
Ответ
Direct transfer of a phosphate group from a metabolic intermediate to ADP to form ATP.
Карточка 289
Вопрос
How does electron transport lead to ATP synthesis in mitochondria?
Ответ
Electron energy pumps protons across the inner membrane; proton flow back through ATP synthase drives ATP formation.
Карточка 290
Вопрос
Why can intense exercise increase lactate production?
Ответ
ATP demand can exceed oxygen delivery and aerobic capacity, so cells regenerate NAD⁺ through lactate formation to sustain glycolysis.
Карточка 291
Вопрос
What is photosynthesis?
Ответ
Conversion of light energy into chemical energy used to synthesize organic molecules from carbon dioxide.
Карточка 292
Вопрос
What is chlorophyll?
Ответ
A green pigment that absorbs light energy for photosynthesis.
Карточка 293
Вопрос
What is an absorption spectrum?
Ответ
A graph showing how strongly a pigment absorbs different wavelengths of light.
Карточка 294
Вопрос
What is an action spectrum?
Ответ
A graph showing the rate or effectiveness of photosynthesis at different wavelengths.
Карточка 295
Вопрос
Which term describes light-driven synthesis of organic molecules from carbon dioxide?
Ответ
photosynthesis
Карточка 296
Вопрос
Which term describes the principal green photosynthetic pigment?
Ответ
chlorophyll
Карточка 297
Вопрос
Which term describes a graph of pigment absorption versus wavelength?
Ответ
an absorption spectrum
Карточка 298
Вопрос
Which term describes a graph of photosynthetic effectiveness versus wavelength?
Ответ
an action spectrum
Карточка 299
Вопрос
What is photolysis of water?
Ответ
Light-driven splitting of water that supplies electrons and hydrogen ions and releases oxygen.
Карточка 300
Вопрос
What are light-dependent reactions?
Ответ
Photosynthetic reactions that use light to generate ATP and reduced electron carriers while releasing oxygen.
Карточка 301
Вопрос
What is the Calvin cycle?
Ответ
A set of chloroplast reactions that uses ATP and reduced electron carriers to convert carbon dioxide into carbohydrate precursors.
Карточка 302
Вопрос
What is carbon fixation?
Ответ
Incorporation of inorganic carbon dioxide into an organic molecule.
Карточка 303
Вопрос
Which term describes light-driven splitting of water?
Ответ
photolysis of water
Карточка 304
Вопрос
Which term describes photosynthetic reactions that directly capture light energy?
Ответ
light-dependent reactions
Карточка 305
Вопрос
Which term describes the carbon-reduction cycle of photosynthesis?
Ответ
the Calvin cycle
Карточка 306
Вопрос
Which term describes incorporation of carbon dioxide into organic matter?
Ответ
carbon fixation
Карточка 307
Вопрос
What is the role of a stoma in photosynthesis?
Ответ
A pore in the leaf epidermis that regulates carbon-dioxide entry as well as water loss.
Карточка 308
Вопрос
What is a limiting factor of photosynthesis?
Ответ
The environmental factor whose availability currently restricts the photosynthetic rate.
Карточка 309
Вопрос
What is the light compensation point?
Ответ
The light intensity at which photosynthetic carbon uptake equals respiratory carbon release.
Карточка 310
Вопрос
What is the overall word equation for oxygenic photosynthesis?
Ответ
Carbon dioxide + water → carbohydrate + oxygen, using light energy.
Карточка 311
Вопрос
Which term describes the regulated leaf pore controlling carbon-dioxide entry for photosynthesis?
Ответ
a stoma
Карточка 312
Вопрос
Which term describes the factor currently restricting photosynthetic rate?
Ответ
a limiting factor
Карточка 313
Вопрос
Which term describes the light level where photosynthesis and respiration balance?
Ответ
the light compensation point
Карточка 314
Вопрос
Where do the main stages of photosynthesis occur in a chloroplast?
Ответ
Light-dependent reactions occur in thylakoid membranes; carbon-fixation reactions occur in the stroma.
Карточка 315
Вопрос
What energy conversion occurs during photosynthesis?
Ответ
Light energy is converted into chemical energy stored first in ATP and reduced carriers and ultimately in organic molecules.
Карточка 316
Вопрос
From which reactant does the oxygen released by photosynthesis originate?
Ответ
Water.
Карточка 317
Вопрос
What role does RuBisCO play in photosynthesis?
Ответ
It catalyzes fixation of carbon dioxide by adding it to an organic acceptor molecule.
Карточка 318
Вопрос
What tradeoff is controlled when stomata open?
Ответ
Opening permits carbon dioxide entry but increases water loss by transpiration.
Карточка 319
Вопрос
Name three leaf features that support photosynthesis.
Ответ
A broad surface captures light, a thin structure shortens diffusion paths, and veins supply water and remove sugars; chloroplast-rich cells and stomata also help.
Карточка 320
Вопрос
What can a plant do with carbohydrate made by photosynthesis?
Ответ
Use it in respiration, convert it to storage or structural carbohydrates, or use its carbon to make lipids, amino acids, and other molecules.
Карточка 321
Вопрос
How are products of the light-dependent reactions used in carbon fixation?
Ответ
ATP supplies energy and NADPH supplies reducing power for conversion of fixed carbon into carbohydrate precursors.
Карточка 322
Вопрос
Why does increasing light intensity eventually stop increasing photosynthetic rate?
Ответ
Another factor, such as carbon dioxide supply, temperature, or biochemical capacity, becomes limiting.
Карточка 323
Вопрос
How can increasing carbon dioxide concentration affect photosynthetic rate?
Ответ
It can increase the rate until another factor becomes limiting.
Карточка 324
Вопрос
Why does photosynthetic rate usually have a temperature optimum?
Ответ
Enzyme-controlled reactions accelerate with temperature up to an optimum, then decline as enzymes and membranes lose effective function.
Карточка 325
Вопрос
Why does an action spectrum broadly resemble the combined absorption spectra of photosynthetic pigments?
Ответ
Wavelengths absorbed by the pigments supply more energy for photosynthesis than poorly absorbed wavelengths.
Карточка 326
Вопрос
What is semiconservative replication?
Ответ
DNA replication in which each daughter molecule contains one parental strand and one newly synthesized strand.
Карточка 327
Вопрос
What is DNA helicase?
Ответ
An enzyme that unwinds the double helix and separates the strands by disrupting base pairing.
Карточка 328
Вопрос
What is DNA polymerase?
Ответ
An enzyme that adds nucleotides to a growing DNA strand using a template.
Карточка 329
Вопрос
What is a primer?
Ответ
A short nucleic-acid segment providing a free 3′ end from which DNA polymerase can extend.
Карточка 330
Вопрос
Which term describes replication producing one old and one new strand per DNA molecule?
Ответ
semiconservative replication
Карточка 331
Вопрос
Which term describes the enzyme that separates DNA strands?
Ответ
DNA helicase
Карточка 332
Вопрос
Which term describes the enzyme that builds DNA from a template?
Ответ
DNA polymerase
Карточка 333
Вопрос
Which term describes the short segment providing a starting 3′ end?
Ответ
a primer
Карточка 334
Вопрос
What is the leading strand?
Ответ
The new DNA strand synthesized continuously toward the replication fork.
Карточка 335
Вопрос
What is the lagging strand?
Ответ
The new DNA strand synthesized discontinuously away from the replication fork.
Карточка 336
Вопрос
What is an Okazaki fragment?
Ответ
A short DNA segment synthesized on the lagging strand.
Карточка 337
Вопрос
What is DNA ligase?
Ответ
An enzyme that seals breaks in the sugar-phosphate backbone, joining DNA fragments.
Карточка 338
Вопрос
Which term describes the continuously synthesized daughter strand?
Ответ
the leading strand
Карточка 339
Вопрос
Which term describes the discontinuously synthesized daughter strand?
Ответ
the lagging strand
Карточка 340
Вопрос
Which term describes a short newly made segment of lagging-strand DNA?
Ответ
an Okazaki fragment
Карточка 341
Вопрос
Which term describes the enzyme that joins DNA fragments by sealing the backbone?
Ответ
DNA ligase
Карточка 342
Вопрос
How does complementary base pairing ensure accurate DNA copying?
Ответ
Each template base specifies the nucleotide added opposite it: A pairs with T, and C pairs with G.
Карточка 343
Вопрос
Why does DNA polymerase synthesize DNA only 5′ to 3′?
Ответ
It can add a nucleotide only to the free 3′ hydroxyl group of the growing strand.
Карточка 344
Вопрос
When in the cell cycle is nuclear DNA replicated?
Ответ
During S phase of interphase, before cell division.
Карточка 345
Вопрос
How can a replication error become a permanent mutation?
Ответ
If it escapes proofreading and repair, the altered sequence can be copied in later cell generations.
Карточка 346
Вопрос
Why are leading and lagging strands synthesized differently?
Ответ
The templates are antiparallel while DNA polymerase works only 5′ to 3′, forcing one strand to be made discontinuously.
Карточка 347
Вопрос
How do proofreading and repair reduce replication errors?
Ответ
Incorrectly paired nucleotides are recognized, removed, and replaced before or after replication continues.
Карточка 348
Вопрос
What three repeating steps amplify DNA in PCR?
Ответ
Strand separation by heating, primer annealing during cooling, and DNA extension by a heat-stable polymerase.
Карточка 349
Вопрос
What determines which DNA region PCR amplifies?
Ответ
The sequences and positions of the two primers flanking the target region.
Карточка 350
Вопрос
What is transcription?
Ответ
Synthesis of RNA from a DNA template.
Карточка 351
Вопрос
What is RNA polymerase?
Ответ
The enzyme that synthesizes RNA complementary to a DNA template strand.
Карточка 352
Вопрос
What is messenger RNA?
Ответ
RNA carrying a coding sequence from DNA to ribosomes.
Карточка 353
Вопрос
What is a codon?
Ответ
A three-base sequence in mRNA that specifies an amino acid or a translation signal.
Карточка 354
Вопрос
Which term describes RNA synthesis from DNA?
Ответ
transcription
Карточка 355
Вопрос
Which term describes the enzyme that builds RNA from a DNA template?
Ответ
RNA polymerase
Карточка 356
Вопрос
Which term describes RNA that carries coding information to ribosomes?
Ответ
messenger RNA
Карточка 357
Вопрос
Which term describes a three-base mRNA unit?
Ответ
a codon
Карточка 358
Вопрос
What is translation?
Ответ
Synthesis of a polypeptide using the codon sequence of mRNA.
Карточка 359
Вопрос
What does a ribosome do during translation?
Ответ
It reads mRNA and catalyzes polypeptide synthesis using its rRNA-protein machinery.
Карточка 360
Вопрос
What is transfer RNA?
Ответ
RNA that carries a specific amino acid and pairs its anticodon with an mRNA codon.
Карточка 361
Вопрос
What is an anticodon?
Ответ
A three-base tRNA sequence complementary to an mRNA codon.
Карточка 362
Вопрос
Which term describes polypeptide synthesis from an mRNA sequence?
Ответ
translation
Карточка 363
Вопрос
Which term describes the translation complex that reads mRNA and builds a polypeptide?
Ответ
a ribosome
Карточка 364
Вопрос
Which term describes the adaptor RNA carrying an amino acid?
Ответ
transfer RNA
Карточка 365
Вопрос
Which term describes the tRNA triplet that pairs with a codon?
Ответ
an anticodon
Карточка 366
Вопрос
What is the genetic code?
Ответ
The set of rules relating mRNA codons to amino acids and translation signals.
Карточка 367
Вопрос
What are start and stop codons?
Ответ
mRNA signals that establish the reading frame or terminate translation.
Карточка 368
Вопрос
Where do transcription and translation occur in a eukaryotic cell?
Ответ
Transcription occurs in the nucleus; translation occurs on ribosomes in the cytoplasm or on rough ER.
Карточка 369
Вопрос
How is an mRNA sequence related to its DNA template strand?
Ответ
It is complementary and antiparallel, with uracil in RNA opposite adenine in DNA.
Карточка 370
Вопрос
Which term describes the codon-to-amino-acid rule set?
Ответ
the genetic code
Карточка 371
Вопрос
Which term describes codons that begin or end translation?
Ответ
start and stop codons
Карточка 372
Вопрос
What reaction does the ribosome catalyze as a polypeptide grows?
Ответ
Formation of peptide bonds between adjacent amino acids.
Карточка 373
Вопрос
What does it mean that the genetic code is degenerate?
Ответ
Most amino acids are specified by more than one codon.
Карточка 374
Вопрос
How can one mRNA produce many polypeptides quickly?
Ответ
Multiple ribosomes can translate the same mRNA simultaneously as a polyribosome.
Карточка 375
Вопрос
Why is translation not the final step in producing many functional proteins?
Ответ
The polypeptide must fold and may undergo cleavage, chemical modification, or assembly with other subunits.
Карточка 376
Вопрос
How does mRNA compare with the DNA coding strand?
Ответ
It has the same base sequence except that RNA contains uracil where DNA contains thymine.
Карточка 377
Вопрос
What happens during eukaryotic RNA splicing?
Ответ
Introns are removed and exons are joined to form mature mRNA.
Карточка 378
Вопрос
Why must codons be read in the correct reading frame?
Ответ
Changing the starting position changes every downstream triplet and therefore the amino-acid sequence.
Карточка 379
Вопрос
How is the correct amino acid matched to each mRNA codon?
Ответ
Each tRNA is charged with a particular amino acid, and its anticodon pairs with the complementary codon.
Карточка 380
Вопрос
How can a base substitution affect a protein?
Ответ
It may be silent, change one amino acid, create a stop codon, or sometimes alter RNA processing.
Карточка 381
Вопрос
What is a mutation?
Ответ
A change in a DNA sequence or chromosome structure that can be passed to daughter cells.
Карточка 382
Вопрос
What is a base substitution?
Ответ
Replacement of one nucleotide pair by another.
Карточка 383
Вопрос
What is an insertion mutation?
Ответ
Addition of one or more nucleotides to a DNA sequence.
Карточка 384
Вопрос
What is a deletion mutation?
Ответ
Loss of one or more nucleotides from a DNA sequence.
Карточка 385
Вопрос
Which term describes a lasting DNA-sequence or chromosome change?
Ответ
a mutation
Карточка 386
Вопрос
Which term describes replacement of one DNA base pair?
Ответ
a base substitution
Карточка 387
Вопрос
Which term describes addition of nucleotides to DNA?
Ответ
an insertion mutation
Карточка 388
Вопрос
Which term describes loss of nucleotides from DNA?
Ответ
a deletion mutation
Карточка 389
Вопрос
What is a frameshift mutation?
Ответ
A coding-sequence insertion or deletion not divisible by three that changes downstream codon grouping.
Карточка 390
Вопрос
What is a silent mutation?
Ответ
A sequence change that does not alter the encoded amino acid.
Карточка 391
Вопрос
What is a missense mutation?
Ответ
A mutation that changes a codon so a different amino acid is incorporated.
Карточка 392
Вопрос
What is a nonsense mutation?
Ответ
A mutation that changes an amino-acid codon into a stop codon.
Карточка 393
Вопрос
Which term describes a mutation that shifts downstream codon grouping?
Ответ
a frameshift mutation
Карточка 394
Вопрос
Which term describes a coding change that leaves the amino acid unchanged?
Ответ
a silent mutation
Карточка 395
Вопрос
Which term describes a mutation causing one amino-acid substitution?
Ответ
a missense mutation
Карточка 396
Вопрос
Which term describes a mutation creating a premature stop codon?
Ответ
a nonsense mutation
Карточка 397
Вопрос
How do germline and somatic mutations differ in inheritance?
Ответ
Germline mutations can enter gametes and be inherited; somatic mutations affect a cell lineage within the individual.
Карточка 398
Вопрос
What can cause mutations?
Ответ
Replication errors, spontaneous chemical changes, radiation, and mutagenic chemicals can alter DNA.
Карточка 399
Вопрос
How does DNA repair protect genome stability?
Ответ
Repair systems detect damaged or mismatched DNA and restore the correct structure or sequence when possible.
Карточка 400
Вопрос
Why are mutations essential to evolution despite often being neutral or harmful?
Ответ
They create new alleles, providing the heritable variation on which selection and drift act.
Карточка 401
Вопрос
What is the basic role of guide RNA in CRISPR gene editing?
Ответ
It directs a nuclease to a complementary DNA sequence.
Карточка 402
Вопрос
Why can the same type of DNA mutation have effects ranging from none to severe?
Ответ
Effects depend on location, genetic-code redundancy, protein role, cell type, and environmental context.
Карточка 403
Вопрос
How can accumulated mutations contribute to cancer?
Ответ
Mutations can activate growth-promoting genes or disable genes that restrain division, repair DNA, or trigger cell death.
Карточка 404
Вопрос
Why can repairing a CRISPR-induced DNA break produce different editing outcomes?
Ответ
Different cellular repair pathways may disrupt the target sequence or use a supplied template for a specific change.
Карточка 405
Вопрос
What is an off-target effect in gene editing?
Ответ
An unintended DNA change at a site sufficiently similar to the intended target.
Карточка 406
Вопрос
Why does heritable human genome editing raise additional ethical concerns?
Ответ
Changes could pass to future generations who cannot consent, with uncertain long-term biological and social effects.
Карточка 407
Вопрос
What is the cell cycle?
Ответ
The ordered sequence of cell growth, DNA replication, nuclear division, and cell division.
Карточка 408
Вопрос
What is interphase?
Ответ
The period of growth, normal activity, and DNA replication between nuclear divisions.
Карточка 409
Вопрос
What is mitosis?
Ответ
Nuclear division that usually produces genetically equivalent daughter nuclei.
Карточка 410
Вопрос
What is cytokinesis?
Ответ
Division of the cytoplasm to form separate daughter cells.
Карточка 411
Вопрос
Which term describes the ordered sequence from one cell division to the next?
Ответ
the cell cycle
Карточка 412
Вопрос
Which term describes the growth and DNA-replication period between divisions?
Ответ
interphase
Карточка 413
Вопрос
Which term describes division producing genetically equivalent nuclei?
Ответ
mitosis
Карточка 414
Вопрос
Which term describes physical division of the cytoplasm?
Ответ
cytokinesis
Карточка 415
Вопрос
What is a chromosome?
Ответ
One DNA molecule packaged with associated proteins.
Карточка 416
Вопрос
What are sister chromatids?
Ответ
The two replicated copies of a chromosome joined before separation.
Карточка 417
Вопрос
What is a centromere?
Ответ
The chromosome region that holds sister chromatids together and organizes kinetochore attachment.
Карточка 418
Вопрос
What is the mitotic spindle?
Ответ
A microtubule system that attaches to and separates chromosomes during cell division.
Карточка 419
Вопрос
Which term describes a protein-packaged DNA molecule?
Ответ
a chromosome
Карточка 420
Вопрос
Which term describes joined replicated copies of one chromosome?
Ответ
sister chromatids
Карточка 421
Вопрос
Which term describes the chromosome region joining sister chromatids?
Ответ
a centromere
Карточка 422
Вопрос
Which term describes the chromosome-separating microtubule system?
Ответ
the mitotic spindle
Карточка 423
Вопрос
What is the basic sequence of mitosis?
Ответ
Chromosomes condense, align at the cell equator, sister chromatids separate to opposite poles, and new nuclei form.
Карточка 424
Вопрос
Why must DNA replicate before mitosis?
Ответ
Each chromosome must have two copies so each daughter nucleus can receive a complete genome.
Карточка 425
Вопрос
Why are daughter cells from mitosis usually genetically similar?
Ответ
Replicated sister chromatids are separated so each daughter receives one copy of every chromosome.
Карточка 426
Вопрос
What are major roles of mitosis in multicellular organisms?
Ответ
Growth, tissue repair, cell replacement, and some forms of asexual reproduction.
Карточка 427
Вопрос
How do homologous chromosomes differ from sister chromatids?
Ответ
Homologs carry the same gene loci but may have different alleles; sister chromatids are replicated copies of one chromosome.
Карточка 428
Вопрос
What key outcome distinguishes mitosis from meiosis?
Ответ
Mitosis usually preserves chromosome number and similarity; meiosis halves chromosome number and generates genetically varied haploid cells.
Карточка 429
Вопрос
How does cytokinesis commonly occur in animal cells?
Ответ
A contractile ring tightens the plasma membrane into a cleavage furrow.
Карточка 430
Вопрос
How does cytokinesis commonly occur in plant cells?
Ответ
Vesicles fuse at the center to form a cell plate that develops into new membranes and a cell wall.
Карточка 431
Вопрос
What is the purpose of cell-cycle checkpoints?
Ответ
They delay progression when conditions are unsuitable or DNA and chromosome attachment are defective.
Карточка 432
Вопрос
How is loss of cell-cycle control related to cancer?
Ответ
Cells can divide despite damage or growth restraints, producing an expanding abnormal clone.
Карточка 433
Вопрос
What is a gene?
Ответ
A DNA sequence that contributes to a functional product and influences a characteristic or cellular process.
Карточка 434
Вопрос
What is an allele?
Ответ
One of the alternative DNA-sequence forms at a gene locus.
Карточка 435
Вопрос
What is a gene locus?
Ответ
The physical position of a gene on a chromosome.
Карточка 436
Вопрос
What is a genotype?
Ответ
The allele combination of an organism at one or more loci.
Карточка 437
Вопрос
Which term describes a functional DNA sequence?
Ответ
a gene
Карточка 438
Вопрос
Which term describes an alternative form of a gene?
Ответ
an allele
Карточка 439
Вопрос
Which term describes a gene's chromosome position?
Ответ
a gene locus
Карточка 440
Вопрос
Which term describes an organism's allele combination?
Ответ
a genotype
Карточка 441
Вопрос
What is a phenotype?
Ответ
An observable or measurable trait produced by genotype and environment.
Карточка 442
Вопрос
What is homozygous?
Ответ
Having two identical alleles at a diploid locus.
Карточка 443
Вопрос
What is heterozygous?
Ответ
Having two different alleles at a diploid locus.
Карточка 444
Вопрос
What is a dominant allele?
Ответ
An allele expressed in the phenotype of a heterozygote under a specified inheritance model.
Карточка 445
Вопрос
Which term describes an observable trait resulting from genes and environment?
Ответ
a phenotype
Карточка 446
Вопрос
Which term describes having two identical alleles at a locus?
Ответ
homozygous
Карточка 447
Вопрос
Which term describes having two different alleles at a locus?
Ответ
heterozygous
Карточка 448
Вопрос
Which term describes an allele expressed in a heterozygote?
Ответ
a dominant allele
Карточка 449
Вопрос
What is a recessive allele?
Ответ
An allele whose phenotype is masked by a dominant allele in a heterozygote.
Карточка 450
Вопрос
What is a genetic carrier?
Ответ
An unaffected heterozygote who can transmit a recessive disease allele.
Карточка 451
Вопрос
What is a test cross?
Ответ
A cross with a homozygous recessive individual used to infer an unknown dominant phenotype's genotype.
Карточка 452
Вопрос
What is a pedigree?
Ответ
A diagram showing biological relationships and occurrence of a trait across generations.
Карточка 453
Вопрос
Which term describes an allele masked in a heterozygote?
Ответ
a recessive allele
Карточка 454
Вопрос
Which term describes an unaffected heterozygote carrying a recessive disease allele?
Ответ
a genetic carrier
Карточка 455
Вопрос
Which term describes a cross used to reveal an unknown dominant genotype?
Ответ
a test cross
Карточка 456
Вопрос
Which term describes a family diagram tracking a trait across generations?
Ответ
a pedigree
Карточка 457
Вопрос
What does allele segregation mean during gamete formation?
Ответ
The two alleles at a diploid locus separate so each gamete receives one.
Карточка 458
Вопрос
What does a Punnett square predict?
Ответ
Expected genotype and phenotype probabilities from specified parental gametes, not guaranteed family outcomes.
Карточка 459
Вопрос
What phenotypic ratio is expected from Aa × Aa with complete dominance?
Ответ
Approximately 3 dominant phenotype : 1 recessive phenotype.
Карточка 460
Вопрос
What genotypic ratio is expected from Aa × Aa?
Ответ
1 AA : 2 Aa : 1 aa.
Карточка 461
Вопрос
What happens in codominance?
Ответ
Both alleles contribute distinctly to the heterozygous phenotype.
Карточка 462
Вопрос
What happens in incomplete dominance?
Ответ
The heterozygote has a phenotype intermediate between the two homozygotes.
Карточка 463
Вопрос
How can environment affect phenotype without changing genotype?
Ответ
Conditions alter development, physiology, or gene expression, changing the observed trait.
Карточка 464
Вопрос
What is the ultimate source of new alleles?
Ответ
Mutation.
Карточка 465
Вопрос
Why are X-linked recessive traits more common in XY individuals?
Ответ
They have only one X chromosome, so one recessive allele on it can determine the phenotype.
Карточка 466
Вопрос
When is the product rule used in genetic probability?
Ответ
For independent events that must both occur; multiply their probabilities.
Карточка 467
Вопрос
When is the sum rule used in genetic probability?
Ответ
For mutually exclusive alternative outcomes; add their probabilities.
Карточка 468
Вопрос
Why do polygenic traits often show continuous variation?
Ответ
Many loci contribute small effects, creating many possible genotypes and phenotypes, often further influenced by environment.
Карточка 469
Вопрос
What pedigree pattern can suggest an autosomal recessive trait?
Ответ
Unaffected parents can have affected children, and all sexes are affected at similar frequencies.
Карточка 470
Вопрос
What is a species?
Ответ
A group of organisms whose members can potentially interbreed and produce fertile offspring under natural conditions.
Карточка 471
Вопрос
What is binomial nomenclature?
Ответ
The two-part scientific naming system using a genus name followed by a specific epithet.
Карточка 472
Вопрос
What is taxonomy?
Ответ
The naming and classification of organisms.
Карточка 473
Вопрос
What is a biological domain?
Ответ
The broadest commonly used taxonomic rank, separating Bacteria, Archaea, and Eukarya.
Карточка 474
Вопрос
Which term describes a naturally interbreeding group producing fertile offspring?
Ответ
a species
Карточка 475
Вопрос
Which term describes the genus-plus-specific-epithet naming system?
Ответ
binomial nomenclature
Карточка 476
Вопрос
Which term describes the science of naming and classifying organisms?
Ответ
taxonomy
Карточка 477
Вопрос
Which term describes the broadest common taxonomic rank?
Ответ
a biological domain
Карточка 478
Вопрос
What is biodiversity?
Ответ
Variation of life at genetic, species, and ecosystem levels.
Карточка 479
Вопрос
What is an autotroph?
Ответ
An organism that makes organic compounds from inorganic carbon using light or chemical energy.
Карточка 480
Вопрос
What is a heterotroph?
Ответ
An organism that obtains organic carbon by consuming other organisms or their products.
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Карточка 481
Вопрос
What is a unicellular organism?
Ответ
An organism consisting of one cell that carries out all essential life functions.
Карточка 482
Вопрос
Which term describes variation of life across genes, species, and ecosystems?
Ответ
biodiversity
Карточка 483
Вопрос
Which term describes an organism that builds organic matter from inorganic carbon?
Ответ
an autotroph
Карточка 484
Вопрос
Which term describes an organism obtaining organic carbon from other organisms?
Ответ
a heterotroph
Карточка 485
Вопрос
Which term describes an organism made of one cell?
Ответ
a unicellular organism
Карточка 486
Вопрос
What is a multicellular organism?
Ответ
An organism composed of many cooperating cells, often with specialized cell types.
Карточка 487
Вопрос
What is a karyotype?
Ответ
An ordered display of chromosomes used to examine their number and large-scale structure.
Карточка 488
Вопрос
What broad feature distinguishes both Bacteria and Archaea from Eukarya?
Ответ
Their cells lack a nucleus and other membrane-bound organelles.
Карточка 489
Вопрос
What features characterize most plant cells?
Ответ
Cellulose walls, chloroplasts in photosynthetic tissues, and large vacuoles are typical features.
Карточка 490
Вопрос
Which term describes an organism made of many cooperating cells?
Ответ
a multicellular organism
Карточка 491
Вопрос
Which term describes an ordered display of an individual's chromosomes?
Ответ
a karyotype
Карточка 492
Вопрос
How do fungi obtain nutrients?
Ответ
They secrete digestive enzymes and absorb soluble products; their cells usually have chitin-containing walls.
Карточка 493
Вопрос
What distinguishes animal nutrition and cell structure?
Ответ
Animals ingest organic material, and their cells lack cell walls and chloroplasts.
Карточка 494
Вопрос
Why are scientific names useful across languages?
Ответ
A standardized name identifies the same organism internationally and reduces ambiguity from local common names.
Карточка 495
Вопрос
Why can genetic diversity improve a population's resilience?
Ответ
More heritable variation increases the chance that some individuals tolerate new diseases or environmental changes.
Карточка 496
Вопрос
What does ecosystem diversity measure?
Ответ
The variety of habitats, communities, and ecological processes within a region.
Карточка 497
Вопрос
Why are Archaea classified separately from Bacteria?
Ответ
They differ in genetic sequences, membrane chemistry, cell-wall composition, and aspects of molecular machinery.
Карточка 498
Вопрос
Why is the biological species concept difficult to apply to fossils or asexual organisms?
Ответ
Their ability to interbreed and produce fertile offspring cannot be tested in the usual way.
Карточка 499
Вопрос
Does a larger chromosome number necessarily mean a more complex organism?
Ответ
No. Chromosome number varies through fusion, fission, and duplication and does not directly measure biological complexity.
Карточка 500
Вопрос
Does genome size reliably predict organismal complexity?
Ответ
No. Large amounts of noncoding and repeated DNA make genome size a poor simple measure of complexity.
Карточка 501
Вопрос
What evidence can be combined when classifying organisms?
Ответ
Molecular sequences, cell structure, anatomy, development, physiology, and reproductive evidence can all contribute.
Карточка 502
Вопрос
What is gas exchange?
Ответ
Diffusion of respiratory gases between an organism and its environment or transport fluid.
Карточка 503
Вопрос
What is ventilation?
Ответ
Bulk movement of air or water over a gas-exchange surface.
Карточка 504
Вопрос
What is an alveolus?
Ответ
A microscopic air sac in the lung where gases diffuse between air and blood.
Карточка 505
Вопрос
What is pulmonary surfactant?
Ответ
A substance lining alveoli that lowers surface tension and reduces collapse.
Карточка 506
Вопрос
Which term describes diffusion of oxygen and carbon dioxide across a respiratory surface?
Ответ
gas exchange
Карточка 507
Вопрос
Which term describes bulk movement of respiratory medium over an exchange surface?
Ответ
ventilation
Карточка 508
Вопрос
Which term describes a microscopic lung air sac?
Ответ
an alveolus
Карточка 509
Вопрос
Which term describes the alveolar lining that lowers surface tension?
Ответ
pulmonary surfactant
Карточка 510
Вопрос
What is the diaphragm?
Ответ
A sheet of skeletal muscle whose contraction increases thoracic volume during inhalation.
Карточка 511
Вопрос
What is tidal volume?
Ответ
The volume of air moved in or out during a normal breath.
Карточка 512
Вопрос
What is a stoma?
Ответ
A regulated epidermal pore through which gases diffuse in leaves.
Карточка 513
Вопрос
What is countercurrent exchange?
Ответ
Exchange between fluids moving in opposite directions, maintaining a gradient along most of the surface.
Карточка 514
Вопрос
Which term describes the muscle sheet that expands the thorax during inhalation?
Ответ
the diaphragm
Карточка 515
Вопрос
Which term describes air volume moved in one normal breath?
Ответ
tidal volume
Карточка 516
Вопрос
Which term describes a regulated leaf gas-exchange pore?
Ответ
a stoma
Карточка 517
Вопрос
Which term describes opposite fluid flow that maintains an exchange gradient?
Ответ
countercurrent exchange
Карточка 518
Вопрос
What features make an efficient gas-exchange surface?
Ответ
Large area, short diffusion distance, permeability, and maintained concentration gradients.
Карточка 519
Вопрос
How is a steep oxygen gradient maintained across alveoli?
Ответ
Ventilation replenishes alveolar oxygen and blood flow removes absorbed oxygen.
Карточка 520
Вопрос
How does diaphragm contraction cause inhalation?
Ответ
Thoracic volume increases, lung pressure falls below atmospheric pressure, and air flows inward.
Карточка 521
Вопрос
What drives quiet exhalation?
Ответ
The diaphragm relaxes and elastic recoil reduces thoracic and lung volume, raising pressure and pushing air out.
Карточка 522
Вопрос
Why do ventilation rate and depth increase during exercise?
Ответ
They increase oxygen uptake and carbon dioxide removal to support higher cellular respiration.
Карточка 523
Вопрос
How does leaf structure shorten the pathway for carbon dioxide diffusion?
Ответ
Stomata open into air spaces, and mesophyll cells expose moist surfaces close to those spaces.
Карточка 524
Вопрос
Why does carbon dioxide diffuse from tissues into blood?
Ответ
Respiring cells produce carbon dioxide, making its partial pressure higher in tissues than in incoming blood.
Карточка 525
Вопрос
How does countercurrent flow improve oxygen uptake at fish gills?
Ответ
Blood continually meets water with a higher oxygen concentration, preserving diffusion along the lamella.
Карточка 526
Вопрос
Why does closing stomata reduce both water loss and photosynthesis?
Ответ
It limits water-vapor diffusion out but also restricts carbon dioxide diffusion into the leaf.
Карточка 527
Вопрос
What is a circulatory system?
Ответ
A transport system that moves a fluid carrying gases, nutrients, wastes, hormones, and heat through an organism.
Карточка 528
Вопрос
What is an artery?
Ответ
A blood vessel carrying blood away from the heart under relatively high pressure.
Карточка 529
Вопрос
What is a vein?
Ответ
A blood vessel carrying blood toward the heart, usually with low pressure and often valves.
Карточка 530
Вопрос
What is a capillary?
Ответ
A microscopic thin-walled vessel where substances exchange between blood and tissues.
Карточка 531
Вопрос
Which term describes an internal fluid-transport system?
Ответ
a circulatory system
Карточка 532
Вопрос
Which term describes a vessel carrying blood away from the heart?
Ответ
an artery
Карточка 533
Вопрос
Which term describes a vessel carrying blood toward the heart?
Ответ
a vein
Карточка 534
Вопрос
Which term describes a microscopic exchange blood vessel?
Ответ
a capillary
Карточка 535
Вопрос
What is the cardiac cycle?
Ответ
The repeating sequence of heart-chamber contraction and relaxation that pumps blood.
Карточка 536
Вопрос
What is hemoglobin?
Ответ
An iron-containing protein in red blood cells that binds oxygen reversibly.
Карточка 537
Вопрос
What is xylem?
Ответ
Plant vascular tissue that transports water and mineral ions and provides structural support.
Карточка 538
Вопрос
What is phloem?
Ответ
Plant vascular tissue that transports sucrose and other organic solutes between sources and sinks.
Карточка 539
Вопрос
Which term describes the repeating pumping sequence of the heart?
Ответ
the cardiac cycle
Карточка 540
Вопрос
Which term describes the oxygen-carrying protein of red blood cells?
Ответ
hemoglobin
Карточка 541
Вопрос
Which term describes plant tissue carrying water and minerals?
Ответ
xylem
Карточка 542
Вопрос
Which term describes plant tissue carrying organic solutes?
Ответ
phloem
Карточка 543
Вопрос
What is transpiration?
Ответ
Loss of water vapor from plant surfaces, mainly through stomata.
Карточка 544
Вопрос
What is phloem translocation?
Ответ
Movement of organic solutes through phloem from sources to sinks.
Карточка 545
Вопрос
How do a source and a sink differ in plant transport?
Ответ
A source releases assimilates to phloem; a sink removes them for use or storage.
Карточка 546
Вопрос
What makes human circulation a double circulation?
Ответ
Blood passes through the heart once in the pulmonary circuit and again in the systemic circuit during one complete journey.
Карточка 547
Вопрос
Which term describes water-vapor loss from plant surfaces?
Ответ
transpiration
Карточка 548
Вопрос
Which term describes movement of organic solutes through phloem?
Ответ
phloem translocation
Карточка 549
Вопрос
Which term describes the exporting and importing regions of phloem transport?
Ответ
source and sink
Карточка 550
Вопрос
How is an artery adapted to high pressure?
Ответ
It has thick elastic and muscular walls and a relatively narrow lumen.
Карточка 551
Вопрос
How is a vein adapted to return low-pressure blood?
Ответ
It has a wide lumen, thinner walls, and valves that reduce backflow.
Карточка 552
Вопрос
How does capillary structure support exchange?
Ответ
One-cell-thick walls give a short diffusion distance; extensive branching gives a large total area; narrow lumens slow flow and keep blood close to tissues.
Карточка 553
Вопрос
What determines whether a heart valve opens or closes?
Ответ
Pressure differences across the valve.
Карточка 554
Вопрос
Trace water from soil to the atmosphere through a plant.
Ответ
Soil → root hairs → root tissues → xylem → leaf mesophyll → leaf air spaces → stomata → atmosphere.
Карточка 555
Вопрос
Why may root cells use active transport to absorb mineral ions?
Ответ
Ion concentrations can be lower in soil than in root cells, so uptake must occur against a gradient.
Карточка 556
Вопрос
Why do large multicellular organisms need bulk transport systems?
Ответ
Their low surface-area-to-volume ratio and long diffusion distances make diffusion alone too slow for whole-body supply.
Карточка 557
Вопрос
Why does hemoglobin unload more oxygen in actively respiring tissues?
Ответ
Lower oxygen and often higher carbon dioxide and acidity reduce hemoglobin's oxygen affinity.
Карточка 558
Вопрос
How does transpiration pull water upward through xylem?
Ответ
Evaporation lowers leaf water potential and creates tension; cohesion transmits the pull through the continuous water column.
Карточка 559
Вопрос
How do wind and low humidity generally affect transpiration?
Ответ
Both maintain a steep water-vapor gradient outside the leaf, increasing transpiration if stomata remain open.
Карточка 560
Вопрос
What drives mass flow in phloem?
Ответ
Sugar loading draws in water and raises pressure at a source; unloading lowers pressure at a sink, producing bulk flow.
Карточка 561
Вопрос
Can the same plant organ be a source at one time and a sink at another?
Ответ
Yes. A storage organ may import sugars while filling and export them later during growth or germination.
Карточка 562
Вопрос
What is a neuron?
Ответ
An excitable cell specialized to receive, process, and transmit information.
Карточка 563
Вопрос
What is a sensory neuron?
Ответ
A neuron carrying information from a receptor toward the central nervous system.
Карточка 564
Вопрос
What is a motor neuron?
Ответ
A neuron carrying commands from the central nervous system to an effector.
Карточка 565
Вопрос
What is the resting potential?
Ответ
The voltage difference across an unstimulated neuron's membrane, with the inside negative relative to outside.
Карточка 566
Вопрос
Which term describes an excitable information-transmitting cell?
Ответ
a neuron
Карточка 567
Вопрос
Which term describes a neuron carrying receptor information to the CNS?
Ответ
a sensory neuron
Карточка 568
Вопрос
Which term describes a neuron carrying CNS commands to an effector?
Ответ
a motor neuron
Карточка 569
Вопрос
Which term describes the negative-inside voltage of an unstimulated neuron?
Ответ
the resting potential
Карточка 570
Вопрос
What is an action potential?
Ответ
A brief, self-propagating reversal and restoration of membrane potential along an excitable membrane.
Карточка 571
Вопрос
What is depolarization?
Ответ
A change that makes membrane potential less negative, and during an action potential often positive.
Карточка 572
Вопрос
What is repolarization?
Ответ
Return of membrane potential toward its resting negative value after depolarization.
Карточка 573
Вопрос
What is a synapse?
Ответ
A junction where one cell communicates with another cell.
Карточка 574
Вопрос
Which term describes a brief propagating change in neuron membrane voltage?
Ответ
an action potential
Карточка 575
Вопрос
Which term describes a membrane-voltage change toward a less negative value?
Ответ
depolarization
Карточка 576
Вопрос
Which term describes return toward resting membrane voltage?
Ответ
repolarization
Карточка 577
Вопрос
Which term describes a communication junction between cells?
Ответ
a synapse
Карточка 578
Вопрос
What is a neurotransmitter?
Ответ
A chemical released by a neuron that changes the activity of a target cell.
Карточка 579
Вопрос
What is the refractory period?
Ответ
A brief period after an action potential when another is impossible or requires a stronger stimulus.
Карточка 580
Вопрос
What is myelin?
Ответ
An insulating sheath around some axons that speeds impulse conduction.
Карточка 581
Вопрос
What happens when membrane depolarization reaches threshold?
Ответ
Voltage-gated channels trigger the self-amplifying events of an action potential.
Карточка 582
Вопрос
Which term describes a neuron-released signaling chemical?
Ответ
a neurotransmitter
Карточка 583
Вопрос
Which term describes the recovery interval after an action potential?
Ответ
the refractory period
Карточка 584
Вопрос
Which term describes the insulating axon sheath?
Ответ
myelin
Карточка 585
Вопрос
What does the all-or-none principle mean for an action potential?
Ответ
Once threshold is reached, the action potential has a characteristic size; stronger stimuli increase frequency, not its amplitude.
Карточка 586
Вопрос
How does myelin increase conduction speed?
Ответ
Depolarizing current travels rapidly beneath myelin and action potentials regenerate mainly at gaps in the sheath.
Карточка 587
Вопрос
What is the basic sequence at a chemical synapse?
Ответ
An impulse triggers neurotransmitter release; it diffuses across the cleft, binds receptors, and alters the postsynaptic cell.
Карточка 588
Вопрос
Why can a reflex response be rapid?
Ответ
A short neural pathway produces an automatic response without waiting for conscious processing.
Карточка 589
Вопрос
What is sensory transduction?
Ответ
Conversion of a physical or chemical stimulus into an electrical signal in a receptor cell.
Карточка 590
Вопрос
How does an action potential propagate along an axon?
Ответ
Local current depolarizes the next membrane region to threshold, opening voltage-gated channels there.
Карточка 591
Вопрос
Why does an action potential normally travel in one direction along an axon?
Ответ
The membrane just behind it is refractory and cannot immediately fire again.
Карточка 592
Вопрос
How is neurotransmitter action ended?
Ответ
The transmitter is removed by enzymatic breakdown, reuptake, or diffusion away.
Карточка 593
Вопрос
What is sensory adaptation?
Ответ
Reduced receptor or neural response during a constant, unchanging stimulus.
Карточка 594
Вопрос
How can a drug alter synaptic transmission?
Ответ
It may mimic or block a transmitter, change its release, or change its removal from the synaptic cleft.
Карточка 595
Вопрос
What is an organ system?
Ответ
A group of organs coordinating to perform major functions for an organism.
Карточка 596
Вопрос
What is a hormone?
Ответ
A signaling molecule released into transport fluid and acting on target cells with suitable receptors.
Карточка 597
Вопрос
What is an endocrine gland?
Ответ
A gland that secretes hormones into extracellular fluid and blood rather than through a duct.
Карточка 598
Вопрос
What is a hormone target cell?
Ответ
A cell able to respond because it has the appropriate receptor.
Карточка 599
Вопрос
Which term describes a coordinated group of organs?
Ответ
an organ system
Карточка 600
Вопрос
Which term describes a long-distance chemical messenger carried in body fluid?
Ответ
a hormone
Карточка 601
Вопрос
Which term describes a ductless hormone-secreting gland?
Ответ
an endocrine gland
Карточка 602
Вопрос
Which term describes a cell with a receptor for a particular hormone?
Ответ
a hormone target cell
Карточка 603
Вопрос
What is digestion?
Ответ
Mechanical and chemical breakdown of food into molecules small enough to absorb.
Карточка 604
Вопрос
What is absorption?
Ответ
Movement of digested nutrients across an exchange surface into blood or lymph.
Карточка 605
Вопрос
What is peristalsis?
Ответ
Coordinated waves of smooth-muscle contraction that move material through the digestive tract.
Карточка 606
Вопрос
What is an intestinal villus?
Ответ
A finger-like projection increasing the absorptive surface of the small intestine.
Карточка 607
Вопрос
Which term describes breakdown of food into absorbable molecules?
Ответ
digestion
Карточка 608
Вопрос
Which term describes movement of digested nutrients into transport fluids?
Ответ
absorption
Карточка 609
Вопрос
Which term describes wave-like gut contractions moving contents?
Ответ
peristalsis
Карточка 610
Вопрос
Which term describes a finger-like intestinal absorption projection?
Ответ
an intestinal villus
Карточка 611
Вопрос
What is excretion?
Ответ
Removal of metabolic waste products from the body.
Карточка 612
Вопрос
What is a nephron?
Ответ
The microscopic functional unit of the kidney that filters blood and modifies filtrate into urine.
Карточка 613
Вопрос
What is ultrafiltration?
Ответ
Pressure-driven filtration of small molecules from blood into a kidney capsule while cells and most proteins remain in blood.
Карточка 614
Вопрос
What is selective reabsorption?
Ответ
Recovery of useful substances and regulated amounts of water and ions from kidney filtrate into blood.
Карточка 615
Вопрос
Which term describes removal of metabolic wastes?
Ответ
excretion
Карточка 616
Вопрос
Which term describes the kidney's microscopic functional unit?
Ответ
a nephron
Карточка 617
Вопрос
Which term describes pressure filtration at the start of a nephron?
Ответ
ultrafiltration
Карточка 618
Вопрос
Which term describes return of useful substances from kidney filtrate to blood?
Ответ
selective reabsorption
Карточка 619
Вопрос
What is skeletal muscle?
Ответ
Striated voluntary muscle attached to the skeleton and used for movement and posture.
Карточка 620
Вопрос
What is an antagonistic muscle pair?
Ответ
Two muscles producing opposite movements at a joint because muscles pull but do not push.
Карточка 621
Вопрос
How do nervous and endocrine signaling generally differ?
Ответ
Neural signals are rapid and targeted; hormonal signals are usually slower, longer-lasting, and distributed through body fluids.
Карточка 622
Вопрос
Why does a circulating hormone affect only some cells?
Ответ
Only target cells express receptors that recognize the hormone and activate a response.
Карточка 623
Вопрос
Which term describes voluntary striated muscle that moves the skeleton?
Ответ
skeletal muscle
Карточка 624
Вопрос
Which term describes two muscles producing opposite joint movements?
Ответ
an antagonistic muscle pair
Карточка 625
Вопрос
What is the final absorbable product of most dietary carbohydrate digestion?
Ответ
Monosaccharides, especially glucose.
Карточка 626
Вопрос
What are the main absorbable products of protein digestion?
Ответ
Amino acids and small peptides that are completed to amino acids during absorption.
Карточка 627
Вопрос
How is the small intestine adapted for absorption?
Ответ
Folds, villi, and microvilli increase area; a thin epithelium, rich blood supply, and lymph vessels support transport.
Карточка 628
Вопрос
Name three integrative roles of the liver.
Ответ
It processes absorbed nutrients, regulates blood chemistry, detoxifies substances, produces bile, and converts ammonia to urea; any three are sufficient.
Карточка 629
Вопрос
Why are blood cells and most plasma proteins absent from normal kidney filtrate?
Ответ
They are too large to cross the filtration barrier.
Карточка 630
Вопрос
How do muscles move a bone at a joint?
Ответ
Contraction shortens the muscle, pulling through a tendon on the bone.
Карточка 631
Вопрос
Why are antagonistic muscles needed at many joints?
Ответ
A muscle can pull in one direction but cannot push itself back, so an opposing muscle produces the reverse movement.
Карточка 632
Вопрос
Why must organ systems be integrated rather than acting independently?
Ответ
Each system depends on materials, signals, waste removal, and stable conditions supplied by other systems.
Карточка 633
Вопрос
Why do many absorbed lipids enter lymph before blood?
Ответ
Intestinal cells package them into lipoprotein particles too large to enter ordinary blood capillaries directly.
Карточка 634
Вопрос
Why is glucose normally absent from final urine?
Ответ
Filtered glucose is selectively reabsorbed into blood when transporter capacity is not exceeded.
Карточка 635
Вопрос
How do respiratory, circulatory, and muscular systems cooperate during exercise?
Ответ
Ventilation supplies oxygen, circulation transports gases and fuels, and muscles use ATP while returning carbon dioxide, heat, and metabolites.
Карточка 636
Вопрос
How do liver, circulation, and kidneys cooperate in nitrogen-waste removal?
Ответ
The liver converts toxic ammonia to urea, blood carries urea, and kidneys filter and excrete it.
Карточка 637
Вопрос
What is a pathogen?
Ответ
A biological agent capable of causing disease.
Карточка 638
Вопрос
What is an antigen?
Ответ
A molecule recognized specifically by an antibody or lymphocyte receptor.
Карточка 639
Вопрос
What is innate immunity?
Ответ
Rapid, nonspecific defense mechanisms present without prior exposure.
Карточка 640
Вопрос
What is adaptive immunity?
Ответ
Specific defense that develops through lymphocyte activation and can form memory.
Карточка 641
Вопрос
Which term describes a disease-causing biological agent?
Ответ
a pathogen
Карточка 642
Вопрос
Which term describes a molecule specifically recognized by adaptive immune receptors?
Ответ
an antigen
Карточка 643
Вопрос
Which term describes rapid nonspecific immune defense?
Ответ
innate immunity
Карточка 644
Вопрос
Which term describes specific immune defense capable of memory?
Ответ
adaptive immunity
Карточка 645
Вопрос
What is a phagocyte?
Ответ
A cell that engulfs and digests microbes, particles, or damaged cells.
Карточка 646
Вопрос
What is a lymphocyte?
Ответ
An adaptive immune cell with receptors specific to particular antigens.
Карточка 647
Вопрос
What is an antibody?
Ответ
A secreted immunoglobulin that binds a specific antigen.
Карточка 648
Вопрос
What is a B lymphocyte?
Ответ
A lymphocyte that can differentiate into antibody-secreting plasma cells and memory cells.
Карточка 649
Вопрос
Which term describes an engulfing immune cell?
Ответ
a phagocyte
Карточка 650
Вопрос
Which term describes an antigen-specific adaptive immune cell?
Ответ
a lymphocyte
Карточка 651
Вопрос
Which term describes a secreted antigen-binding immunoglobulin?
Ответ
an antibody
Карточка 652
Вопрос
Which term describes the lymphocyte lineage that produces antibody-secreting cells?
Ответ
a B lymphocyte
Карточка 653
Вопрос
What is a helper T cell?
Ответ
A lymphocyte that coordinates immune responses through contact signals and cytokines.
Карточка 654
Вопрос
What is an immune memory cell?
Ответ
A long-lived lymphocyte that responds rapidly after re-exposure to its antigen.
Карточка 655
Вопрос
What is vaccination?
Ответ
Deliberate exposure to a safe form or component of an antigen to generate protective immune memory.
Карточка 656
Вопрос
What is an antibiotic?
Ответ
A substance that kills bacteria or inhibits their growth at clinically useful doses.
Карточка 657
Вопрос
Which term describes the T cell that coordinates other immune cells?
Ответ
a helper T cell
Карточка 658
Вопрос
Which term describes a long-lived lymphocyte enabling faster re-exposure response?
Ответ
an immune memory cell
Карточка 659
Вопрос
Which term describes safe antigen exposure used to create immune memory?
Ответ
vaccination
Карточка 660
Вопрос
Which term describes a drug acting against bacteria?
Ответ
an antibiotic
Карточка 661
Вопрос
What are examples of first-line defenses against pathogens?
Ответ
Intact skin, mucus, cilia, antimicrobial secretions, stomach acidity, and competing microbiota.
Карточка 662
Вопрос
How does inflammation help defend damaged tissue?
Ответ
It increases local blood flow and vessel permeability and recruits immune cells and defensive molecules.
Карточка 663
Вопрос
What happens during phagocytosis?
Ответ
A cell surrounds a particle in a vesicle, then fuses it with digestive compartments to destroy or process it.
Карточка 664
Вопрос
How can antibodies help eliminate a pathogen?
Ответ
They can neutralize targets, block attachment, clump particles, and mark them for phagocytosis or complement attack.
Карточка 665
Вопрос
Why can a vaccine generate protection without causing the full disease?
Ответ
It presents antigen in a weakened, inactivated, partial, or encoded form that stimulates immunity with much lower risk.
Карточка 666
Вопрос
Why do antibiotics not treat viral infections?
Ответ
Viruses lack the bacterial structures and independent metabolic processes targeted by antibiotics.
Карточка 667
Вопрос
What determines the antigen specificity of a lymphocyte?
Ответ
The molecular shape and chemistry of its unique surface receptor.
Карточка 668
Вопрос
What is clonal selection?
Ответ
An antigen activates lymphocytes with matching receptors, causing them to proliferate and differentiate.
Карточка 669
Вопрос
Why is a secondary adaptive immune response usually faster and stronger?
Ответ
Memory cells are more numerous and activate rapidly, producing effective cells and antibodies sooner.
Карточка 670
Вопрос
How can high vaccination coverage protect some unvaccinated people?
Ответ
Reduced transmission makes encounters with infectious individuals less likely, though protection is incomplete and pathogen-dependent.
Карточка 671
Вопрос
How does antibiotic use select for resistant bacteria?
Ответ
Susceptible bacteria are removed while resistant variants survive and reproduce, increasing resistance-allele frequency.
Карточка 672
Вопрос
Why can unnecessary or incomplete antibiotic exposure promote resistance?
Ответ
It creates selection favoring resistant cells while potentially leaving surviving bacteria to multiply and spread.
Карточка 673
Вопрос
What is an allergy?
Ответ
An immune response to a normally harmless antigen that causes tissue symptoms or damage.
Карточка 674
Вопрос
What is asexual reproduction?
Ответ
Production of offspring from one parent without fusion of gametes.
Карточка 675
Вопрос
What is sexual reproduction?
Ответ
Production of offspring involving fusion of haploid gametes.
Карточка 676
Вопрос
What is a gamete?
Ответ
A haploid reproductive cell able to fuse with another gamete.
Карточка 677
Вопрос
What is fertilization?
Ответ
Fusion of gamete nuclei to form a diploid zygote.
Карточка 678
Вопрос
Which term describes reproduction without gamete fusion?
Ответ
asexual reproduction
Карточка 679
Вопрос
Which term describes reproduction involving gamete fusion?
Ответ
sexual reproduction
Карточка 680
Вопрос
Which term describes a haploid reproductive cell?
Ответ
a gamete
Карточка 681
Вопрос
Which term describes fusion of gamete nuclei?
Ответ
fertilization
Карточка 682
Вопрос
What is a zygote?
Ответ
The diploid cell formed by fertilization.
Карточка 683
Вопрос
What is meiosis?
Ответ
Cell division that halves chromosome number and usually produces genetically varied haploid cells.
Карточка 684
Вопрос
What is ovulation?
Ответ
Release of a secondary oocyte from an ovary.
Карточка 685
Вопрос
What is implantation?
Ответ
Attachment and embedding of an early embryo in the uterine lining.
Карточка 686
Вопрос
Which term describes the first diploid cell after fertilization?
Ответ
a zygote
Карточка 687
Вопрос
Which term describes division producing varied haploid cells?
Ответ
meiosis
Карточка 688
Вопрос
Which term describes release of an oocyte from an ovary?
Ответ
ovulation
Карточка 689
Вопрос
Which term describes embedding of an early embryo in the uterine lining?
Ответ
implantation
Карточка 690
Вопрос
What is the placenta?
Ответ
A temporary organ that exchanges materials between maternal and fetal blood supplies without normally mixing them directly.
Карточка 691
Вопрос
What is pollination?
Ответ
Transfer of pollen from an anther to a receptive stigma.
Карточка 692
Вопрос
Why does sexual reproduction usually produce more genetic variation than asexual reproduction?
Ответ
Meiosis reshuffles alleles and random fertilization combines genomes from two gametes.
Карточка 693
Вопрос
Why must gametes be haploid?
Ответ
Fusion of two haploid gametes restores the diploid chromosome number instead of doubling it each generation.
Карточка 694
Вопрос
Which term describes the maternal-fetal exchange organ?
Ответ
the placenta
Карточка 695
Вопрос
Which term describes transfer of pollen to a stigma?
Ответ
pollination
Карточка 696
Вопрос
What are major roles of FSH in the ovarian cycle?
Ответ
It stimulates follicle development and supports estrogen secretion.
Карточка 697
Вопрос
What is a major role of the mid-cycle LH surge?
Ответ
It triggers ovulation and formation of the corpus luteum.
Карточка 698
Вопрос
How does estrogen contribute to the uterine cycle?
Ответ
It promotes repair and thickening of the uterine lining after menstruation.
Карточка 699
Вопрос
How does progesterone contribute to the uterine cycle?
Ответ
It maintains a thick, secretory uterine lining after ovulation.
Карточка 700
Вопрос
Where does human fertilization usually occur?
Ответ
In an oviduct, before the early embryo reaches the uterus.
Карточка 701
Вопрос
What happens after compatible pollen reaches a flower's stigma?
Ответ
A pollen tube grows toward an ovule and delivers male nuclei for fertilization.
Карточка 702
Вопрос
Why does menstruation usually begin if pregnancy does not occur?
Ответ
The corpus luteum degenerates, progesterone and estrogen fall, and the uterine lining is no longer maintained.
Карточка 703
Вопрос
What substances commonly cross the placenta between mother and fetus?
Ответ
Oxygen and nutrients move toward the fetus; carbon dioxide and nitrogenous wastes move toward the mother.
Карточка 704
Вопрос
How can contraception prevent pregnancy in different ways?
Ответ
Methods can inhibit ovulation, block sperm from reaching an egg, prevent fertilization, or permanently interrupt the reproductive ducts.
Карточка 705
Вопрос
What is homeostasis?
Ответ
Maintenance of internal conditions within ranges compatible with normal function despite change.
Карточка 706
Вопрос
What is negative feedback?
Ответ
Control in which a deviation triggers responses that oppose the original change.
Карточка 707
Вопрос
What is a set point?
Ответ
The target value or range around which a regulated variable is maintained.
Карточка 708
Вопрос
What is a homeostatic receptor?
Ответ
A sensor that detects a change in a regulated variable.
Карточка 709
Вопрос
Which term describes maintenance of a stable functional internal environment?
Ответ
homeostasis
Карточка 710
Вопрос
Which term describes feedback that counteracts a deviation?
Ответ
negative feedback
Карточка 711
Вопрос
Which term describes the target around which a variable is regulated?
Ответ
a set point
Карточка 712
Вопрос
Which term describes the sensor in a feedback system?
Ответ
a homeostatic receptor
Карточка 713
Вопрос
What is a control center?
Ответ
The component that compares information with a target and coordinates a response.
Карточка 714
Вопрос
What is an effector?
Ответ
A muscle, gland, or other component that carries out a control response.
Карточка 715
Вопрос
What is thermoregulation?
Ответ
Control of body temperature within a functional range.
Карточка 716
Вопрос
What is vasodilation?
Ответ
Widening of blood vessels, often increasing blood flow near the skin.
Карточка 717
Вопрос
Which term describes the feedback component that evaluates input and directs a response?
Ответ
a control center
Карточка 718
Вопрос
Which term describes the component that executes a physiological response?
Ответ
an effector
Карточка 719
Вопрос
Which term describes physiological regulation of body temperature?
Ответ
thermoregulation
Карточка 720
Вопрос
Which term describes widening of blood vessels?
Ответ
vasodilation
Карточка 721
Вопрос
What is vasoconstriction?
Ответ
Narrowing of blood vessels, often reducing blood flow near the skin.
Карточка 722
Вопрос
What is insulin?
Ответ
A pancreatic hormone that lowers elevated blood glucose by promoting uptake and storage.
Карточка 723
Вопрос
What is glucagon?
Ответ
A pancreatic hormone that raises low blood glucose by promoting release of stored fuel.
Карточка 724
Вопрос
What are the main components of a homeostatic feedback loop?
Ответ
A regulated variable, receptor, control center, effectors, and responses that alter the variable.
Карточка 725
Вопрос
Which term describes narrowing of blood vessels?
Ответ
vasoconstriction
Карточка 726
Вопрос
Which term describes the pancreatic hormone that lowers blood glucose?
Ответ
insulin
Карточка 727
Вопрос
Which term describes the pancreatic hormone that raises blood glucose?
Ответ
glucagon
Карточка 728
Вопрос
What happens when blood glucose rises after a meal?
Ответ
Insulin secretion increases, promoting glucose uptake and storage so blood glucose falls toward its normal range.
Карточка 729
Вопрос
What happens when blood glucose falls during fasting?
Ответ
Glucagon secretion increases, promoting glycogen breakdown and glucose release by the liver.
Карточка 730
Вопрос
How does sweating cool the body?
Ответ
Evaporation of water from skin transfers heat to the environment.
Карточка 731
Вопрос
How does skin vasodilation increase heat loss?
Ответ
It brings more warm blood near the surface, increasing transfer of heat to the environment.
Карточка 732
Вопрос
How does shivering warm the body?
Ответ
Rapid involuntary muscle contractions increase respiration and heat production.
Карточка 733
Вопрос
Does homeostasis keep internal conditions perfectly constant?
Ответ
No. Variables fluctuate within controlled ranges around target values.
Карточка 734
Вопрос
How does ADH help conserve water?
Ответ
It increases water permeability in kidney collecting ducts, so more water is reabsorbed and urine becomes more concentrated.
Карточка 735
Вопрос
How should ADH secretion change during dehydration?
Ответ
It should increase, promoting greater water reabsorption by the kidneys.
Карточка 736
Вопрос
How does positive feedback differ from negative feedback?
Ответ
Positive feedback amplifies a change until an endpoint; negative feedback opposes a change and stabilizes a variable.
Карточка 737
Вопрос
Why can diabetes mellitus cause persistently high blood glucose?
Ответ
Insulin production may be insufficient or target cells may respond poorly to insulin.
Карточка 738
Вопрос
What is biological evolution?
Ответ
Change in heritable characteristics or allele frequencies of a population across generations.
Карточка 739
Вопрос
What is allele frequency?
Ответ
The proportion of gene copies in a population represented by a particular allele.
Карточка 740
Вопрос
What is microevolution?
Ответ
Evolutionary change in allele frequencies within populations over relatively short timescales.
Карточка 741
Вопрос
What is speciation?
Ответ
Evolutionary formation of new species.
Карточка 742
Вопрос
Which term describes change in a population's heritable composition across generations?
Ответ
biological evolution
Карточка 743
Вопрос
Which term describes the proportion of a population's gene copies that are one allele?
Ответ
allele frequency
Карточка 744
Вопрос
Which term describes short-timescale allele-frequency change within populations?
Ответ
microevolution
Карточка 745
Вопрос
Which term describes formation of new species?
Ответ
speciation
Карточка 746
Вопрос
What is reproductive isolation?
Ответ
Barriers that prevent or greatly reduce gene flow between populations.
Карточка 747
Вопрос
What is allopatric speciation?
Ответ
Speciation after populations become geographically separated and diverge.
Карточка 748
Вопрос
What is sympatric speciation?
Ответ
Speciation without geographic separation, through reproductive isolation within the same area.
Карточка 749
Вопрос
What are homologous structures?
Ответ
Structures similar because they were inherited from a common ancestor, even if their functions differ.
Карточка 750
Вопрос
Which term describes barriers reducing gene flow between populations?
Ответ
reproductive isolation
Карточка 751
Вопрос
Which term describes speciation following geographic separation?
Ответ
allopatric speciation
Карточка 752
Вопрос
Which term describes speciation within the same geographic area?
Ответ
sympatric speciation
Карточка 753
Вопрос
Which term describes structures similar through common ancestry?
Ответ
homologous structures
Карточка 754
Вопрос
What are analogous structures?
Ответ
Structures with similar functions that evolved independently rather than from the same ancestral structure.
Карточка 755
Вопрос
What is a common ancestor?
Ответ
An ancestral population from which two or more descendant lineages evolved.
Карточка 756
Вопрос
How does the fossil record provide evidence for evolution?
Ответ
It documents organisms from different times, including appearance, change, persistence, and extinction of lineages.
Карточка 757
Вопрос
How do DNA and protein sequences provide evidence of common ancestry?
Ответ
Shared sequences are inherited; greater similarity generally indicates more recent common ancestry.
Карточка 758
Вопрос
Which term describes functionally similar structures of independent evolutionary origin?
Ответ
analogous structures
Карточка 759
Вопрос
Which term describes an ancestral population shared by descendant lineages?
Ответ
a common ancestor
Карточка 760
Вопрос
What is the evolutionary significance of extinction?
Ответ
It permanently ends a lineage and can alter ecological opportunities and the future diversification of survivors.
Карточка 761
Вопрос
Do individual organisms evolve during their lifetimes?
Ответ
No. Individuals develop and acclimate; evolution is heritable change in populations across generations.
Карточка 762
Вопрос
Why is evolution represented as a branching tree rather than a ladder?
Ответ
Lineages split from common ancestors; living species are not arranged as stages toward a single goal.
Карточка 763
Вопрос
How can island species support evolutionary explanations?
Ответ
Their similarities to nearby mainland ancestors and unique local adaptations fit divergence after colonization and isolation.
Карточка 764
Вопрос
How can geographic isolation lead to reproductive isolation?
Ответ
Separated populations accumulate different mutations and experience different selection and drift until interbreeding is reduced.
Карточка 765
Вопрос
Why can continuing gene flow slow speciation?
Ответ
Movement of alleles between populations counteracts genetic divergence.
Карточка 766
Вопрос
Why can unrelated species evolve similar traits?
Ответ
Similar environmental challenges can favor similar functional solutions through convergent evolution.
Карточка 767
Вопрос
Which parts of evolution are random and which are nonrandom?
Ответ
Mutation and many sampling effects are random with respect to need; natural selection nonrandomly favors variants that reproduce better in a given environment.
Карточка 768
Вопрос
What is conservation biology?
Ответ
The science and practice of protecting biodiversity, ecological processes, and evolutionary potential.
Карточка 769
Вопрос
What is habitat fragmentation?
Ответ
Division of continuous habitat into smaller, isolated patches.
Карточка 770
Вопрос
What is an endangered species?
Ответ
A species facing a high risk of extinction in the wild.
Карточка 771
Вопрос
What is in situ conservation?
Ответ
Protection of species in their natural habitats and ecological communities.
Карточка 772
Вопрос
Which term describes the protection of biodiversity and ecological processes?
Ответ
conservation biology
Карточка 773
Вопрос
Which term describes division of habitat into isolated patches?
Ответ
habitat fragmentation
Карточка 774
Вопрос
Which term describes a species at high risk of extinction?
Ответ
an endangered species
Карточка 775
Вопрос
Which term describes conservation within natural habitat?
Ответ
in situ conservation
Карточка 776
Вопрос
What is ex situ conservation?
Ответ
Protection of organisms or genetic material outside the natural habitat.
Карточка 777
Вопрос
What is a population bottleneck?
Ответ
A sharp population reduction that can remove genetic variation by chance.
Карточка 778
Вопрос
What is a wildlife corridor?
Ответ
Habitat connecting isolated patches to permit movement and gene flow.
Карточка 779
Вопрос
What major human-driven processes threaten biodiversity?
Ответ
Habitat loss, overexploitation, invasive species, pollution, and climate change.
Карточка 780
Вопрос
Which term describes conservation outside natural habitat?
Ответ
ex situ conservation
Карточка 781
Вопрос
Which term describes a severe population reduction that loses genetic diversity?
Ответ
a population bottleneck
Карточка 782
Вопрос
Which term describes habitat linking isolated populations?
Ответ
a wildlife corridor
Карточка 783
Вопрос
What makes a protected area more effective than a boundary alone?
Ответ
Adequate size, representative habitat, enforcement, connectivity, local support, and management of external threats.
Карточка 784
Вопрос
Why is long-term population monitoring important in conservation?
Ответ
It reveals trends, tests whether management works, and provides early warning of decline.
Карточка 785
Вопрос
How can ecosystem services support the case for conservation?
Ответ
Healthy ecosystems provide benefits such as pollination, water purification, carbon storage, soil formation, and cultural value.
Карточка 786
Вопрос
Why are very small populations especially vulnerable to extinction?
Ответ
Chance events, inbreeding, low genetic diversity, and difficulty finding mates can reinforce decline.
Карточка 787
Вопрос
What are benefits and limits of captive-breeding programs?
Ответ
They can prevent immediate extinction and manage breeding, but may lose diversity, alter behavior, and fail without safe habitat for release.
Карточка 788
Вопрос
Why can controlling an invasive species aid conservation?
Ответ
It can reduce predation, competition, disease, or habitat alteration affecting native species.
Карточка 789
Вопрос
Why must conservation priorities consider more than species count?
Ответ
Endemism, evolutionary distinctness, ecological roles, threat severity, feasibility, and human needs also matter.
Карточка 790
Вопрос
What is an adaptation?
Ответ
A heritable characteristic that increases reproductive success in a particular environment.
Карточка 791
Вопрос
What is acclimation?
Ответ
A reversible physiological or behavioral adjustment by an individual to environmental change.
Карточка 792
Вопрос
What is a structural adaptation?
Ответ
An inherited anatomical feature that improves performance in an environment.
Карточка 793
Вопрос
What is a physiological adaptation?
Ответ
An inherited functional or biochemical feature that improves performance in an environment.
Карточка 794
Вопрос
Which term describes a heritable trait improving reproductive success in context?
Ответ
an adaptation
Карточка 795
Вопрос
Which term describes an individual's reversible adjustment to environmental change?
Ответ
acclimation
Карточка 796
Вопрос
Which term describes an adaptive anatomical feature?
Ответ
a structural adaptation
Карточка 797
Вопрос
Which term describes an adaptive functional or biochemical feature?
Ответ
a physiological adaptation
Карточка 798
Вопрос
What is a behavioral adaptation?
Ответ
An inherited behavior pattern that improves survival or reproduction.
Карточка 799
Вопрос
What is an environmental tolerance range?
Ответ
The range of an abiotic condition within which an organism can survive and reproduce.
Карточка 800
Вопрос
What is evolutionary fitness?
Ответ
Relative contribution of an individual or genotype to future generations.
Карточка 801
Вопрос
How can a thick cuticle and reduced leaves help a desert plant?
Ответ
The cuticle lowers surface permeability, while smaller leaves reduce the area from which water can evaporate.
Карточка 802
Вопрос
Which term describes an adaptive behavior pattern?
Ответ
a behavioral adaptation
Карточка 803
Вопрос
Which term describes the survivable range of an abiotic condition?
Ответ
an environmental tolerance range
Карточка 804
Вопрос
Which term describes relative reproductive contribution to future generations?
Ответ
evolutionary fitness
Карточка 805
Вопрос
How can a streamlined body adapt an aquatic animal to movement?
Ответ
It reduces drag, lowering the energy needed to move through water.
Карточка 806
Вопрос
Does an organism develop an adaptation because it needs one?
Ответ
No. Heritable variants arise without regard to need, and selection changes their frequencies across generations.
Карточка 807
Вопрос
Why may organisms from different thermal environments have enzymes with different temperature optima?
Ответ
Selection favors protein structures that balance flexibility and stability under local temperatures.
Карточка 808
Вопрос
Why is an adaptation rarely beneficial in every environment?
Ответ
Traits carry costs and their advantage depends on local resources, competitors, predators, and physical conditions.
Карточка 809
Вопрос
How does phenotypic plasticity differ from genetic adaptation?
Ответ
Plasticity lets one genotype produce different phenotypes; adaptation is a heritable population trait shaped across generations.
Карточка 810
Вопрос
What is local adaptation?
Ответ
A population has higher fitness in its home environment than foreign populations because selection favored local traits.
Карточка 811
Вопрос
What is an ecological niche?
Ответ
The set of environmental conditions, resources, interactions, and functional roles associated with a species.
Карточка 812
Вопрос
What is a habitat?
Ответ
The physical place or environment where an organism lives.
Карточка 813
Вопрос
What is a fundamental niche?
Ответ
The full range of conditions and resources a species could use without limiting biotic interactions.
Карточка 814
Вопрос
What is a realized niche?
Ответ
The conditions and resources a species actually uses after competition and other interactions.
Карточка 815
Вопрос
Which term describes a species' environmental requirements and ecological role?
Ответ
an ecological niche
Карточка 816
Вопрос
Which term describes the place where an organism lives?
Ответ
a habitat
Карточка 817
Вопрос
Which term describes the potential niche without limiting biotic interactions?
Ответ
a fundamental niche
Карточка 818
Вопрос
Which term describes the niche actually occupied in nature?
Ответ
a realized niche
Карточка 819
Вопрос
What is competition?
Ответ
An interaction in which organisms reduce one another's access to a limited resource.
Карточка 820
Вопрос
What is mutualism?
Ответ
An interaction in which both participating species benefit.
Карточка 821
Вопрос
What is predation?
Ответ
An interaction in which one organism kills and consumes another.
Карточка 822
Вопрос
How does a habitat differ from a niche?
Ответ
A habitat is where an organism lives; a niche includes how it uses conditions and resources and interacts there.
Карточка 823
Вопрос
Which term describes an interaction over a limited resource that harms both competitors?
Ответ
competition
Карточка 824
Вопрос
Which term describes an interspecific interaction benefiting both partners?
Ответ
mutualism
Карточка 825
Вопрос
Which term describes an interaction where one organism kills and eats another?
Ответ
predation
Карточка 826
Вопрос
What kinds of factors define a niche?
Ответ
Abiotic factors such as temperature and moisture, plus biotic factors such as food, competitors, predators, and partners.
Карточка 827
Вопрос
What does competitive exclusion predict?
Ответ
Species with effectively identical niches cannot coexist indefinitely under stable conditions; one is excluded or niches diverge.
Карточка 828
Вопрос
How can resource partitioning reduce competition?
Ответ
Species use different resources, places, or times, reducing niche overlap.
Карточка 829
Вопрос
What is a keystone species?
Ответ
A species whose effect on community structure is disproportionately large relative to its abundance.
Карточка 830
Вопрос
Why can an introduced species expand rapidly in a new community?
Ответ
It may encounter abundant resources, suitable climate, and fewer predators, pathogens, or competitors.
Карточка 831
Вопрос
Can an organism alter the niche conditions of other species?
Ответ
Yes. Ecosystem engineers modify habitat structure or resource availability, changing opportunities for other organisms.
Карточка 832
Вопрос
What is a population?
Ответ
Individuals of the same species living in the same area at the same time.
Карточка 833
Вопрос
What is an ecological community?
Ответ
Populations of different species living and interacting in an area.
Карточка 834
Вопрос
What is an ecosystem?
Ответ
A community together with its physical environment and their interactions.
Карточка 835
Вопрос
What is carrying capacity?
Ответ
The population size an environment can sustain over time under given conditions.
Карточка 836
Вопрос
Which term describes same-species individuals sharing an area and time?
Ответ
a population
Карточка 837
Вопрос
Which term describes interacting populations of different species?
Ответ
an ecological community
Карточка 838
Вопрос
Which term describes a community plus its abiotic environment?
Ответ
an ecosystem
Карточка 839
Вопрос
Which term describes the long-term supportable population size?
Ответ
carrying capacity
Карточка 840
Вопрос
What is population density?
Ответ
The number of individuals per unit area or volume.
Карточка 841
Вопрос
What is a limiting factor?
Ответ
A resource or condition that restricts population growth or distribution.
Карточка 842
Вопрос
What is a density-dependent factor?
Ответ
A factor whose effect strengthens as population density increases.
Карточка 843
Вопрос
What is a density-independent factor?
Ответ
A factor whose effect is not primarily determined by population density.
Карточка 844
Вопрос
Which term describes individuals per unit area or volume?
Ответ
population density
Карточка 845
Вопрос
Which term describes a resource or condition restricting a population?
Ответ
a limiting factor
Карточка 846
Вопрос
Which term describes a factor with stronger effects at higher density?
Ответ
a density-dependent factor
Карточка 847
Вопрос
Which term describes a factor acting largely regardless of population density?
Ответ
a density-independent factor
Карточка 848
Вопрос
What is exponential population growth?
Ответ
Growth at a constant per-capita rate, producing a J-shaped curve under ideal conditions.
Карточка 849
Вопрос
What is logistic population growth?
Ответ
Growth that slows as population size approaches carrying capacity, producing an S-shaped model.
Карточка 850
Вопрос
What four processes directly change population size?
Ответ
Births and immigration increase it; deaths and emigration decrease it.
Карточка 851
Вопрос
Under what conditions can exponential growth occur temporarily?
Ответ
Resources are abundant and limiting effects such as competition, disease, and predation are weak.
Карточка 852
Вопрос
Which term describes J-shaped growth at constant per-capita rate?
Ответ
exponential population growth
Карточка 853
Вопрос
Which term describes S-shaped growth that slows near carrying capacity?
Ответ
logistic population growth
Карточка 854
Вопрос
Why is infectious disease often density dependent?
Ответ
Close or frequent contact at high density increases transmission opportunities.
Карточка 855
Вопрос
Give an example of a density-independent population factor.
Ответ
A severe storm, wildfire, drought, or freeze can affect populations regardless of their initial density.
Карточка 856
Вопрос
When is quadrat sampling useful?
Ответ
For estimating abundance or frequency of sessile or slow-moving organisms in defined areas.
Карточка 857
Вопрос
What can a transect reveal?
Ответ
How species occurrence or abundance changes along an environmental gradient.
Карточка 858
Вопрос
What can happen when a population overshoots carrying capacity?
Ответ
Resource depletion may raise mortality or lower reproduction, causing decline or oscillation.
Карточка 859
Вопрос
What is the basic mark–recapture estimate of population size?
Ответ
First sample marked × second sample total ÷ marked individuals recaptured.
Карточка 860
Вопрос
What assumptions improve a mark–recapture estimate?
Ответ
Marks persist and do not affect survival, marked individuals mix, capture probability is similar, and the population is effectively closed.
Карточка 861
Вопрос
Why does a correlation between two population variables not prove causation?
Ответ
A third factor, reverse influence, chance, or biased sampling could produce the association.
Карточка 862
Вопрос
What is a trophic level?
Ответ
A feeding position in a food chain or web.
Карточка 863
Вопрос
What is a producer?
Ответ
An autotroph that converts inorganic carbon into organic matter.
Карточка 864
Вопрос
What is a consumer?
Ответ
An organism obtaining energy and matter by eating other organisms or organic material.
Карточка 865
Вопрос
What is a decomposer?
Ответ
An organism that externally digests dead material and wastes and absorbs the products.
Карточка 866
Вопрос
Which term describes a feeding position in an ecosystem?
Ответ
a trophic level
Карточка 867
Вопрос
Which term describes an autotroph forming organic matter?
Ответ
a producer
Карточка 868
Вопрос
Which term describes an organism feeding on other organic matter?
Ответ
a consumer
Карточка 869
Вопрос
Which term describes an organism digesting dead organic matter externally?
Ответ
a decomposer
Карточка 870
Вопрос
What is a food chain?
Ответ
A linear representation of feeding and energy-transfer relationships.
Карточка 871
Вопрос
What is a food web?
Ответ
A network of interconnected feeding relationships in a community.
Карточка 872
Вопрос
What is gross primary productivity?
Ответ
The total rate at which producers capture energy into organic matter.
Карточка 873
Вопрос
What is net primary productivity?
Ответ
Producer energy stored as new biomass after subtracting producer respiration from gross primary productivity.
Карточка 874
Вопрос
Which term describes a linear feeding sequence?
Ответ
a food chain
Карточка 875
Вопрос
Which term describes a network of connected food chains?
Ответ
a food web
Карточка 876
Вопрос
Which term describes the total producer energy-capture rate?
Ответ
gross primary productivity
Карточка 877
Вопрос
Which term describes producer biomass gain after respiration?
Ответ
net primary productivity
Карточка 878
Вопрос
What is ecological productivity?
Ответ
The rate of biomass or energy production per unit area or volume.
Карточка 879
Вопрос
What is a biogeochemical cycle?
Ответ
Movement of an element or compound through organisms and the physical environment.
Карточка 880
Вопрос
Why is less energy available at each higher trophic level?
Ответ
Not all biomass is eaten or digested, and organisms use energy in respiration, movement, maintenance, and heat loss.
Карточка 881
Вопрос
Why does energy flow rather than cycle through an ecosystem?
Ответ
Energy enters mainly as light and ultimately disperses as heat, which ecosystems cannot fully recycle.
Карточка 882
Вопрос
Which term describes the rate of biomass or energy production?
Ответ
ecological productivity
Карточка 883
Вопрос
Which term describes cycling of matter through living and nonliving reservoirs?
Ответ
a biogeochemical cycle
Карточка 884
Вопрос
Why can matter cycle through an ecosystem?
Ответ
Atoms are conserved and repeatedly transferred among organisms, detritus, soil, water, and atmosphere.
Карточка 885
Вопрос
Why is a pyramid of energy always upright?
Ответ
Usable energy decreases between trophic levels because every transfer includes losses.
Карточка 886
Вопрос
How are gross and net primary productivity related?
Ответ
NPP = GPP − producer respiration.
Карточка 887
Вопрос
How do decomposers support nutrient cycling?
Ответ
They break down dead material and wastes, releasing inorganic nutrients for reuse.
Карточка 888
Вопрос
What processes move carbon rapidly between organisms and the atmosphere?
Ответ
Photosynthesis removes carbon dioxide; respiration, decomposition, and combustion release it.
Карточка 889
Вопрос
Why is nitrogen fixation important?
Ответ
It converts atmospheric nitrogen gas into forms that can enter biological nitrogen metabolism.
Карточка 890
Вопрос
How can excess nitrogen or phosphorus cause eutrophication?
Ответ
Nutrient enrichment drives algal growth; decomposition of the biomass consumes oxygen and can create hypoxic water.
Карточка 891
Вопрос
Why can a persistent pollutant reach higher concentrations at higher trophic levels?
Ответ
Predators consume contaminant stored in many prey, and the substance is not readily broken down or excreted.
Карточка 892
Вопрос
How is trophic-transfer efficiency calculated?
Ответ
Energy or biomass gained by the higher trophic level ÷ energy or biomass available at the lower level × 100%.
Карточка 893
Вопрос
What is phenotypic variation?
Ответ
Differences in observable traits among individuals of a population.
Карточка 894
Вопрос
What is heritable variation?
Ответ
Trait differences that can be transmitted genetically to offspring.
Карточка 895
Вопрос
What is a selection pressure?
Ответ
An environmental factor causing differences in survival or reproduction among phenotypes.
Карточка 896
Вопрос
What is relative fitness?
Ответ
An individual's reproductive success compared with others in the population.
Карточка 897
Вопрос
Which term describes observable differences among individuals?
Ответ
phenotypic variation
Карточка 898
Вопрос
Which term describes genetically transmissible trait differences?
Ответ
heritable variation
Карточка 899
Вопрос
Which term describes an environmental factor producing differential reproductive success?
Ответ
a selection pressure
Карточка 900
Вопрос
Which term describes reproductive success relative to other individuals?
Ответ
relative fitness
Карточка 901
Вопрос
What is directional selection?
Ответ
Selection favoring one extreme phenotype and shifting a population's trait distribution.
Карточка 902
Вопрос
What is stabilizing selection?
Ответ
Selection favoring intermediate phenotypes and acting against extremes.
Карточка 903
Вопрос
What is disruptive selection?
Ответ
Selection favoring both extreme phenotypes over intermediates.
Карточка 904
Вопрос
What is sexual selection?
Ответ
Selection arising from differences in mating success.
Карточка 905
Вопрос
Which term describes selection shifting a trait toward one extreme?
Ответ
directional selection
Карточка 906
Вопрос
Which term describes selection favoring intermediate phenotypes?
Ответ
stabilizing selection
Карточка 907
Вопрос
Which term describes selection favoring both trait extremes?
Ответ
disruptive selection
Карточка 908
Вопрос
Which term describes selection caused by unequal mating success?
Ответ
sexual selection
Карточка 909
Вопрос
What conditions are required for natural selection?
Ответ
Individuals vary, some variation is heritable, more offspring are produced than can reproduce, and variants differ in reproductive success.
Карточка 910
Вопрос
How does natural selection produce antibiotic-resistant bacterial populations?
Ответ
Existing resistant variants survive treatment and reproduce more than susceptible bacteria.
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Вопрос
Does an antibiotic cause bacteria to mutate specifically toward resistance?
Ответ
No. Resistance variants arise without regard to need; treatment selects among them.
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Вопрос
Can an individual become genetically adapted through natural selection?
Ответ
No. Selection acts on individuals, but adaptation is a population change across generations.
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Вопрос
How does artificial selection differ from natural selection?
Ответ
Humans choose breeding traits in artificial selection; environmental conditions determine differential reproduction in natural selection.
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Вопрос
How does natural selection change a population?
Ответ
Individuals with advantageous heritable variants leave more offspring, increasing those alleles over generations.
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Вопрос
Why is fitness environment-dependent?
Ответ
A trait that improves reproduction in one environment may be neutral or costly in another.
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Вопрос
How does genetic drift differ from natural selection?
Ответ
Drift changes allele frequencies by chance sampling; selection changes them through consistent fitness differences.
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Вопрос
What is ecosystem stability?
Ответ
The capacity of an ecosystem to maintain or recover its structure and functions despite disturbance.
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Вопрос
What is an ecological tipping point?
Ответ
A threshold beyond which feedbacks can drive a large and difficult-to-reverse ecosystem shift.
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Вопрос
What is a mesocosm?
Ответ
A controlled, simplified ecosystem used to investigate ecological processes under more realistic conditions than a small laboratory vessel.
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Вопрос
What is a sustainable yield?
Ответ
A harvest rate that can continue without causing long-term resource decline under prevailing conditions.
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Вопрос
Which term describes the capacity of an ecosystem to persist or recover after disturbance?
Ответ
ecosystem stability
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Вопрос
Which term describes a threshold triggering a major hard-to-reverse ecosystem shift?
Ответ
an ecological tipping point
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Вопрос
Which term describes a controlled model ecosystem used for experiments?
Ответ
a mesocosm
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Вопрос
Which term describes a harvest rate that avoids long-term depletion?
Ответ
a sustainable yield
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Вопрос
What is eutrophication?
Ответ
Nutrient enrichment of water that stimulates excess primary production and can lead to oxygen depletion.
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Вопрос
What is biomagnification?
Ответ
Increase in concentration of a persistent pollutant at successively higher trophic levels.
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Вопрос
What is rewilding?
Ответ
Ecosystem restoration that rebuilds natural processes, species interactions, and self-sustaining ecological function.
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Вопрос
What features can make an ecosystem more stable?
Ответ
Diverse functional roles, connected habitats, intact food webs, nutrient cycling, and balancing feedbacks can help the system resist or recover from disturbance.
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Вопрос
Which term describes nutrient enrichment that can deplete oxygen in water?
Ответ
eutrophication
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Вопрос
Which term describes increasing pollutant concentration up a food chain?
Ответ
biomagnification
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Вопрос
Which term describes restoration focused on natural processes and self-sustaining ecosystems?
Ответ
rewilding
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Вопрос
How could extensive Amazon deforestation push the ecosystem toward a tipping point?
Ответ
Loss of trees can reduce rainfall recycling and increase heat and fire, which cause further forest loss and may shift large areas toward a drier state.
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Вопрос
What are a benefit and a limitation of using a mesocosm?
Ответ
It allows controlled experiments with interacting organisms, but its simplified scale cannot reproduce every process or long-term influence in a natural ecosystem.
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Вопрос
Why should a fishery harvest below an uncertain maximum sustainable yield?
Ответ
Population estimates and recruitment vary, so a safety margin reduces the chance that error or a poor breeding year drives long-term decline.
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Вопрос
How can intensive agriculture reduce ecosystem stability?
Ответ
Habitat loss, low crop diversity, soil degradation, heavy water use, pesticides, and nutrient runoff can weaken food webs and ecosystem processes.
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Вопрос
Why can microplastic pollution harm aquatic ecosystems?
Ответ
Small persistent particles can be ingested, carry additives or other pollutants, damage feeding and tissues, and move through food webs.
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Вопрос
How can rewilding improve ecosystem stability?
Ответ
Restoring native species, habitat connections, and natural disturbance or grazing processes can rebuild feedbacks and allow the ecosystem to maintain itself with less intervention.
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Вопрос
What is the greenhouse effect?
Ответ
Warming caused when atmospheric gases absorb and re-emit outgoing infrared radiation.
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Вопрос
What is a greenhouse gas?
Ответ
An atmospheric gas that absorbs infrared radiation at wavelengths emitted by Earth.
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Вопрос
What is carbon dioxide (CO₂)?
Ответ
A long-lived greenhouse gas increased mainly by fossil-fuel combustion, cement production, and land-use change.
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Вопрос
What is methane (CH₄)?
Ответ
A potent greenhouse gas emitted by sources including fossil-fuel systems, livestock, rice cultivation, wetlands, and waste.
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Вопрос
Which term describes warming from absorption and re-emission of infrared radiation?
Ответ
the greenhouse effect
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Вопрос
Which term describes an atmospheric infrared-absorbing gas?
Ответ
a greenhouse gas
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Вопрос
Which term describes the long-lived greenhouse gas strongly increased by fossil fuels?
Ответ
carbon dioxide (CO₂)
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Вопрос
Which term describes the potent short-lived greenhouse gas from biological and fossil sources?
Ответ
methane (CH₄)
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Вопрос
What is albedo?
Ответ
The fraction of incoming radiation reflected by a surface.
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Вопрос
What is a carbon sink?
Ответ
A reservoir that absorbs more carbon than it releases over a specified period.
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Вопрос
What is ocean acidification?
Ответ
Decline in seawater pH caused mainly by absorption of human-emitted carbon dioxide.
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Вопрос
What is climate change?
Ответ
A persistent change in the statistical patterns of climate over decades or longer.
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Вопрос
Which term describes surface reflectivity?
Ответ
albedo
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Вопрос
Which term describes a reservoir with net carbon uptake?
Ответ
a carbon sink
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Вопрос
Which term describes seawater pH decline from absorbed carbon dioxide?
Ответ
ocean acidification
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Вопрос
Which term describes long-term change in climate patterns?
Ответ
climate change
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Вопрос
What is the enhanced greenhouse effect?
Ответ
Additional warming caused by human-driven increases in greenhouse-gas concentrations.
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Вопрос
How do climate mitigation and climate adaptation differ?
Ответ
Mitigation limits the magnitude of climate change; adaptation reduces harm from changes that occur.
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Вопрос
How does increasing greenhouse-gas concentration alter Earth's energy balance?
Ответ
Less outgoing infrared energy initially escapes to space, so the climate warms until energy balance is restored at a higher temperature.
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Вопрос
How can melting ice amplify warming?
Ответ
Less bright ice lowers albedo, so darker land or water absorbs more solar energy and causes further warming.
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Вопрос
How can climate change alter species distributions?
Ответ
Temperature, rainfall, seasons, sea level, and interactions shift, moving or shrinking areas with suitable conditions.
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Вопрос
Why can ocean acidification harm calcifying organisms?
Ответ
Carbonate chemistry changes, reducing availability of carbonate ions used to build calcium-carbonate structures.
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Вопрос
How can ecosystem protection contribute to climate mitigation?
Ответ
Protecting forests, wetlands, soils, and coastal habitats can avoid emissions and maintain or increase carbon storage.

Luminous sequence of molecular forms, a cell, a leaf and animal silhouette, and a water ecosystem on a dark blue background.

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