AP Biology Flashcards: Complete 8-Unit Course Review
Review all 8 AP Biology units with original flashcards for concepts, pathways, experimental design, data interpretation, and FRQ reasoning.
关于这套卡组
AP Biology Flashcards: Complete 8-Unit Course Review
The current AP Biology framework covers eight units, from chemistry of life through ecology. This 540-card deck turns that full course into short, original retrieval prompts, with science-practice reasoning mixed into the biology instead of parked in a separate section.
What the cards practice
The cards connect terms to functions, structures to consequences, pathway steps to inputs, outputs, locations, and regulation, and evidence to biological claims. Separate prompts cover useful reverse mappings when they are real study tasks—for example, identifying a process from its location or choosing the inference supported by a result. Short original scenarios also practice describing patterns, explaining mechanisms, predicting changes, justifying claims, setting up calculations, and evaluating evidence.
The deck does not mechanically reverse every definition or pathway. It leaves out copied exam material, scoring language, official figures, exhaustive protocols, broad essay prompts, textbook-specific trivia, and advanced-college details outside the current course boundary.
Learning order
The sequence follows Units 1–8. Within each unit it moves from prerequisites to processes, applications, experiments, data, and FRQ-style reasoning, while spacing close variants apart. Long-term spacing and interleaving are left to the review scheduler.
What still needs practice
Flashcards are useful for recall and small reasoning moves, but they cannot replace laboratory work, graph construction, extended data analysis, or timed multiple-choice and free-response practice. Use the deck beside class labs and full original practice questions.
Scope and provenance
The course boundary was reviewed on September 1, 2026 against the College Board AP Biology course page, the Fall 2025 Course and Exam Description, its current clarifications and corrections, the 2026–27 course-change table, and the current exam page. The selection, prompts, answers, examples, sequence, metadata, and cover are independently created from common biological knowledge and source checks. No exam questions, scoring guidelines, CED text, answer keys, or official figures were copied or transformed.
The Common knowledge · CC0 1.0 label applies to the original wording, organization, metadata, and generated media to the extent applicable rights exist. It does not claim ownership of biological facts, AP or College Board names, or third-party source material.
This independent, unofficial study deck is not affiliated with, endorsed by, or sponsored by College Board. AP and College Board names identify the course and exam only. Official requirements: https://apcentral.collegeboard.org/courses/ap-biology
这套卡组中的卡片
卡片 1
问题
Why is a water molecule polar?
答案
Oxygen pulls shared electrons more strongly than hydrogen, giving oxygen a partial negative charge and the hydrogens partial positive charges.
卡片 2
问题
Which elements make up most biological molecules?
答案
Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur—often shortened to CHNOPS.
卡片 3
问题
What is the relationship between a monomer and a polymer?
答案
Monomers are small building blocks; polymers are chains or networks made from repeated monomers.
卡片 4
问题
What is a monosaccharide's main role in cells?
答案
It can provide quick energy and serve as a building block for larger carbohydrates.
卡片 5
问题
Why do lipids mix poorly with water?
答案
Most of their bonds are nonpolar, so water cannot form favorable interactions with them.
卡片 6
问题
What three parts make up a nucleotide?
答案
A five-carbon sugar, a phosphate group, and a nitrogenous base.
卡片 7
问题
What parts of an amino acid vary and stay constant?
答案
The amino group, carboxyl group, hydrogen, and central carbon are shared; the side chain, or R group, varies.
卡片 8
问题
What does pH measure?
答案
The negative logarithm of hydrogen-ion concentration; lower pH means more hydrogen ions.
卡片 9
问题
What is a hydrogen bond in liquid water?
答案
A weak attraction between a partially positive hydrogen on one water molecule and a partially negative oxygen on another.
卡片 10
问题
How does an unsaturated fatty acid differ from a saturated one?
答案
An unsaturated fatty acid has at least one carbon–carbon double bond; a saturated fatty acid has none.
卡片 11
问题
What bond links amino acids in a polypeptide?
答案
A peptide bond.
卡片 12
问题
What does dehydration synthesis do?
答案
It joins subunits with a covalent bond while removing the elements of water.
卡片 13
问题
How does cohesion help water move through a plant?
答案
Hydrogen bonds keep water molecules linked, helping a continuous column rise through xylem.
卡片 14
问题
How do plants and animals differ in short-term glucose storage?
答案
Plants store glucose mainly as starch; animals store it mainly as glycogen.
卡片 15
问题
What determines a protein's primary structure?
答案
Its amino-acid sequence.
卡片 16
问题
How does a cis double bond affect a fatty-acid tail?
答案
It introduces a bend that prevents neighboring tails from packing tightly.
卡片 17
问题
How does adhesion support water transport in narrow tubes?
答案
Water sticks to polar surfaces, helping it resist gravity along cell walls.
卡片 18
问题
Which base pairing distinguishes RNA from DNA?
答案
RNA uses uracil, so adenine pairs with uracil instead of thymine.
卡片 19
问题
What stabilizes common protein secondary structures?
答案
Hydrogen bonds between atoms in the polypeptide backbone.
卡片 20
问题
Why can carbon form so many biological structures?
答案
It has four valence electrons and can form four stable covalent bonds, including chains, branches, and rings.
卡片 21
问题
Why can some insects stand on water?
答案
Cohesion among surface water molecules creates high surface tension.
卡片 22
问题
What does hydrolysis do to a biological polymer?
答案
It adds the elements of water to break a covalent bond between subunits.
卡片 23
问题
What carbohydrate strengthens plant cell walls?
答案
Cellulose.
卡片 24
问题
Why are fats useful for long-term energy storage?
答案
Their many C–H bonds store substantial chemical energy, and hydrophobic storage adds little water mass.
卡片 25
问题
How does water buffer rapid temperature change?
答案
Breaking and forming many hydrogen bonds absorbs or releases substantial heat, giving water a high specific heat.
卡片 26
问题
What does antiparallel mean for a DNA double helix?
答案
Its two strands run in opposite directions: one 5′→3′ and the other 3′→5′.
卡片 27
问题
What mainly drives a protein's tertiary structure?
答案
Interactions among side chains, including hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.
卡片 28
问题
What is a trace element?
答案
An element an organism needs in very small amounts, such as iron in many electron-transfer proteins.
卡片 29
问题
Why does sweating cool an organism?
答案
The fastest water molecules escape as vapor, carrying heat away from the surface.
卡片 30
问题
A cell builds a polysaccharide from sugars. Is water consumed or released?
答案
Released. Forming each linkage by dehydration removes water.
卡片 31
问题
Why can branching help a storage polysaccharide release glucose quickly?
答案
More branch ends give enzymes more sites to work at once.
卡片 32
问题
What makes a phospholipid amphipathic?
答案
It has a polar, hydrophilic head and nonpolar, hydrophobic tails.
卡片 33
问题
Where is biological information encoded in a nucleic acid?
答案
In the linear sequence of nucleotide bases.
卡片 34
问题
What is quaternary protein structure?
答案
The arrangement of two or more polypeptide subunits into one functional protein.
卡片 35
问题
Why does ice float on liquid water?
答案
Stable hydrogen bonds hold ice molecules in an open lattice, making ice less dense than liquid water.
卡片 36
问题
How does electronegativity affect a covalent bond?
答案
A difference in attraction for electrons makes electron sharing unequal and can create a polar bond.
卡片 37
问题
A digestive reaction adds water while splitting a macromolecule. What reaction is this?
答案
Hydrolysis.
卡片 38
问题
What links monosaccharides in a polysaccharide?
答案
Glycosidic covalent bonds.
卡片 39
问题
Why do phospholipids form bilayers in water?
答案
Hydrophilic heads face water while hydrophobic tails cluster away from it.
卡片 40
问题
To which end are nucleotides added during nucleic-acid synthesis?
答案
The 3′ end of the growing strand.
卡片 41
问题
Why can one amino-acid substitution change protein function?
答案
It can alter side-chain interactions, folding, stability, or an active or binding site.
卡片 42
问题
How does a buffer resist a pH change?
答案
It can accept added hydrogen ions or donate them when hydrogen-ion concentration falls.
卡片 43
问题
Why is water a useful solvent for cells?
答案
Its partial charges surround ions and other polar molecules, separating and dispersing them.
卡片 44
问题
Why do functional groups matter in organic molecules?
答案
They give carbon skeletons predictable chemical properties, such as polarity, acidity, or reactivity.
卡片 45
问题
Why can two polymers built from similar monomers have different functions?
答案
Their monomer sequence, branching, length, and three-dimensional shape can differ.
卡片 46
问题
A seedling consumes stored starch. What happens to the starch?
答案
Hydrolysis breaks it into smaller sugars that can enter energy pathways.
卡片 47
问题
What are two biological roles of steroids?
答案
Some act as signaling molecules, and cholesterol helps stabilize animal cell membranes.
卡片 48
问题
What bond forms the backbone of a nucleic-acid strand?
答案
Covalent phosphodiester bonds link the sugar of one nucleotide to the phosphate of the next.
卡片 49
问题
What does denaturation do to a protein?
答案
It disrupts the protein's three-dimensional shape and often its function without usually breaking the primary peptide chain.
卡片 50
问题
An enzyme works best near pH 7 but slows at pH 3. What is a likely explanation?
答案
Extra hydrogen ions changed charges and interactions that maintain the enzyme's active shape.
卡片 51
问题
What structure encloses every cell?
答案
A plasma membrane.
卡片 52
问题
What is the nucleus's main function?
答案
It houses most eukaryotic DNA and is a major site of DNA replication and transcription.
卡片 53
问题
Why does surface-area-to-volume ratio fall as a cell grows?
答案
Volume increases with the cube of length, while surface area increases with the square.
卡片 54
问题
What does the fluid mosaic model describe?
答案
A dynamic phospholipid bilayer containing mobile proteins, sterols, and carbohydrates.
卡片 55
问题
What drives simple diffusion?
答案
Random molecular motion produces net movement from higher to lower concentration.
卡片 56
问题
How does active transport differ from facilitated diffusion?
答案
Active transport moves a substance against its gradient using energy; facilitated diffusion moves it down a gradient.
卡片 57
问题
Why does compartmentalization increase cellular efficiency?
答案
It concentrates enzymes and substrates and maintains distinct conditions for different reactions.
卡片 58
问题
When should a light microscope be preferred over an electron microscope?
答案
When observing living cells or dynamic processes at lower resolution.
卡片 59
问题
What does the nucleolus produce?
答案
Ribosomal RNA and early ribosome subunits.
卡片 60
问题
Does passive transport require direct cellular energy?
答案
No. It moves substances down an electrochemical or concentration gradient.
卡片 61
问题
What feature separates prokaryotic from eukaryotic cells?
答案
Eukaryotic cells have a membrane-bound nucleus and other membrane-bound organelles; prokaryotic cells do not.
卡片 62
问题
Which membrane region blocks most ions and polar molecules?
答案
The hydrophobic interior formed by phospholipid tails.
卡片 63
问题
What happens on rough endoplasmic reticulum?
答案
Bound ribosomes make proteins for secretion, membranes, or the endomembrane system.
卡片 64
问题
How does facilitated diffusion differ from simple diffusion?
答案
It uses a channel or carrier protein but still moves a substance down its gradient.
卡片 65
问题
Where is prokaryotic DNA usually located?
答案
In a nucleoid region rather than inside a membrane-bound nucleus.
卡片 66
问题
How does cholesterol affect an animal membrane?
答案
It buffers fluidity, limiting excess movement when warm and preventing tight packing when cool.
卡片 67
问题
What does smooth endoplasmic reticulum do?
答案
It synthesizes lipids, detoxifies some compounds, and stores calcium in specialized cells.
卡片 68
问题
What determines a channel protein's selectivity?
答案
Its pore size, shape, charge, and gating behavior.
卡片 69
问题
What does the sodium–potassium pump accomplish?
答案
Using ATP, it exports three sodium ions and imports two potassium ions per cycle.
卡片 70
问题
What do ribosomes do in both prokaryotic and eukaryotic cells?
答案
They translate mRNA into polypeptides.
卡片 71
问题
What is the Golgi apparatus's role?
答案
It modifies, sorts, and packages proteins and lipids arriving from the endoplasmic reticulum.
卡片 72
问题
What is osmosis?
答案
Net movement of water across a selectively permeable membrane toward lower free-water concentration.
卡片 73
问题
Why does a high surface-area-to-volume ratio help a cell?
答案
It provides more membrane area per unit of cytoplasm for exchange with the environment.
卡片 74
问题
How do unsaturated phospholipid tails affect membrane fluidity?
答案
Their bends reduce tight packing, usually increasing fluidity.
卡片 75
问题
Trace a secreted protein after translation begins.
答案
Rough ER → transport vesicle → Golgi → secretory vesicle → plasma membrane.
卡片 76
问题
What happens to an animal cell in a hypotonic solution?
答案
Water enters; the cell swells and may lyse.
卡片 77
问题
What is cotransport?
答案
The downhill movement of one substance powers the uphill transport of another through the same protein.
卡片 78
问题
What is the main role of a cell wall?
答案
It provides structural support and helps prevent excessive expansion.
卡片 79
问题
What do lysosomes do?
答案
Their hydrolytic enzymes digest macromolecules and recycle damaged cell parts in an acidic compartment.
卡片 80
问题
What happens to an animal cell in a hypertonic solution?
答案
Water leaves; the cell shrinks.
卡片 81
问题
How do intestinal microvilli improve absorption?
答案
They increase membrane surface area without greatly increasing cell volume.
卡片 82
问题
What can an integral membrane protein do?
答案
It can transport substances, receive signals, catalyze reactions, or anchor cell structures.
卡片 83
问题
What is a central vacuole's major role in a plant cell?
答案
It stores solutes and water and helps maintain turgor pressure.
卡片 84
问题
What happens to a plant cell in a hypotonic solution?
答案
Water enters and turgor pressure rises; the cell wall helps prevent bursting.
卡片 85
问题
How can a proton gradient power sucrose uptake in a plant cell?
答案
Protons flow down their gradient through a symporter that carries sucrose uphill.
卡片 86
问题
What evidence supports the endosymbiotic origin of mitochondria?
答案
They have double membranes, circular DNA, bacterial-like ribosomes, and divide independently by a similar process.
卡片 87
问题
Which overall energy-conversion pathway mainly occurs in mitochondria?
答案
Most stages of aerobic cellular respiration and ATP production.
卡片 88
问题
What happens to a plant cell in a hypertonic solution?
答案
Water leaves, turgor falls, and the membrane may pull from the wall during plasmolysis.
卡片 89
问题
Why can't a standard light microscope resolve a ribosome clearly?
答案
A ribosome is smaller than the microscope's diffraction-limited resolution.
卡片 90
问题
How do bacterial and plant cell walls differ?
答案
Bacterial walls usually contain peptidoglycan; plant walls contain cellulose.
卡片 91
问题
Which overall energy-conversion pathway occurs in chloroplasts?
答案
Photosynthesis: converting light energy into chemical energy and fixing carbon.
卡片 92
问题
A cubical cell doubles each side length. How do surface area and volume change?
答案
Surface area increases 4-fold; volume increases 8-fold.
卡片 93
问题
What is the role of membrane carbohydrates?
答案
They help cells recognize and interact with one another.
卡片 94
问题
What is water potential?
答案
A measure predicting water movement; water moves from higher to lower water potential.
卡片 95
问题
How do microtubules support a cell?
答案
They resist compression, form tracks for motors, and build structures such as spindles, cilia, and flagella.
卡片 96
问题
What is endocytosis?
答案
The plasma membrane folds inward to bring material into the cell in a vesicle.
卡片 97
问题
What evidence supports the endosymbiotic origin of chloroplasts?
答案
They share bacterial-like DNA, ribosomes, division, and a double membrane consistent with engulfment.
卡片 98
问题
In a membrane-permeability test, what is the independent variable?
答案
The factor deliberately changed, such as temperature or solute identity.
卡片 99
问题
How do microfilaments support cell movement?
答案
Actin filaments interact with motor proteins to change cell shape, contract, and move materials.
卡片 100
问题
What does the cytosol contain?
答案
Water, ions, small molecules, and proteins where many metabolic reactions occur.
卡片 101
问题
Why can diffusion limit cell size?
答案
As dimensions grow, molecules must travel farther, while exchange area does not keep pace with metabolic volume.
卡片 102
问题
What does selective permeability mean?
答案
The membrane allows some substances to cross more readily than others.
卡片 103
问题
What is an intermediate filament's general role?
答案
It provides durable mechanical strength and helps anchor structures.
卡片 104
问题
How does adding a nonpenetrating solute affect water potential?
答案
It makes solute potential, and usually total water potential, more negative.
卡片 105
问题
What is exocytosis?
答案
A vesicle fuses with the plasma membrane and releases contents outside the cell.
卡片 106
问题
Why can lysosomal enzymes digest safely inside a cell?
答案
A membrane isolates the acidic enzymes from most cytosolic components.
卡片 107
问题
Why include an untreated membrane sample in an experiment?
答案
It provides a control baseline for judging the treatment's effect.
卡片 108
问题
Why doesn't cell size alone identify whether a cell is prokaryotic?
答案
Sizes overlap; the presence or absence of internal membrane-bound structures is stronger evidence.
卡片 109
问题
Why are organelle interactions important?
答案
Cell functions often require products to move through several specialized compartments rather than one organelle working alone.
卡片 110
问题
What graph would show a size constraint clearly?
答案
Plot cell size on the x-axis and surface-area-to-volume ratio on the y-axis; the ratio should decline as size rises.
卡片 111
问题
Which molecules cross a phospholipid bilayer most easily without proteins?
答案
Small nonpolar molecules, such as oxygen and carbon dioxide.
卡片 112
问题
Two solutions have equal water potential. What is the net water movement?
答案
None, although water molecules still move both ways.
卡片 113
问题
Why is ATP loss likely to disrupt ion balance?
答案
ATP-powered pumps stop maintaining gradients, so passive leaks move ions toward equilibrium.
卡片 114
问题
How does folding an internal membrane help an organelle?
答案
It increases surface area for membrane-bound reactions without a matching increase in volume.
卡片 115
问题
A dye leaves heated cells faster than unheated cells. What conclusion is supported?
答案
Heating increased membrane permeability under the tested conditions; the data alone do not identify the exact molecular damage.
卡片 116
问题
What does an enzyme change in a reaction?
答案
It lowers activation energy, increasing reaction rate without changing the reaction's overall free-energy change.
卡片 117
问题
What makes a reaction exergonic?
答案
It releases free energy and has a negative change in free energy under the stated conditions.
卡片 118
问题
What are the overall inputs and outputs of photosynthesis?
答案
Carbon dioxide and water use light energy to produce carbohydrate and oxygen.
卡片 119
问题
What are the overall reactants and products of aerobic cellular respiration?
答案
Organic fuel and oxygen are converted mainly to carbon dioxide, water, and ATP, with heat released.
卡片 120
问题
How should reaction rate be calculated from product data?
答案
Divide the change in product amount by the elapsed time.
卡片 121
问题
What makes an enzyme substrate-specific?
答案
The active site's shape and chemical properties favor particular substrates.
卡片 122
问题
Where do the light reactions occur?
答案
In the thylakoid membranes of chloroplasts.
卡片 123
问题
Where does glycolysis occur?
答案
In the cytosol.
卡片 124
问题
What makes a reaction endergonic?
答案
It requires a net input of free energy and has a positive change in free energy.
卡片 125
问题
What is induced fit?
答案
Substrate binding shifts the enzyme's shape into a form that better supports catalysis.
卡片 126
问题
Where does the Calvin cycle occur?
答案
In the chloroplast stroma.
卡片 127
问题
What does glycolysis produce per glucose?
答案
Two pyruvate, a net two ATP, and two NADH.
卡片 128
问题
How can cells drive an endergonic reaction?
答案
They couple it to a sufficiently exergonic reaction so the combined free-energy change is negative.
卡片 129
问题
Why isn't an enzyme consumed by the reaction it catalyzes?
答案
It returns to a reusable form after products leave the active site.
卡片 130
问题
What do photosynthetic pigments do?
答案
They absorb particular wavelengths and transfer excitation energy into the light reactions.
卡片 131
问题
Does glycolysis require oxygen directly?
答案
No. It can run without oxygen if NAD⁺ is regenerated.
卡片 132
问题
What does ATP hydrolysis commonly provide?
答案
Usable free energy and a phosphate group that can change a molecule's reactivity or protein shape.
卡片 133
问题
How does substrate concentration affect rate at low concentrations?
答案
Rate usually rises because more substrate molecules collide with available active sites.
卡片 134
问题
Why do chlorophyll-containing leaves reflect green light?
答案
Chlorophyll absorbs green wavelengths less strongly than red and blue wavelengths.
卡片 135
问题
Where does pyruvate oxidation occur in a eukaryotic cell?
答案
In the mitochondrial matrix.
卡片 136
问题
Why is ATP called an energy-coupling molecule?
答案
Its hydrolysis links energy-releasing processes to cellular work.
卡片 137
问题
Why does enzyme rate plateau at high substrate concentration?
答案
Most active sites are occupied, so enzyme amount becomes limiting.
卡片 138
问题
What is photolysis of water?
答案
Light-driven splitting of water that supplies electrons and protons and releases oxygen.
卡片 139
问题
What happens during pyruvate oxidation?
答案
Each pyruvate becomes acetyl-CoA, releasing carbon dioxide and reducing NAD⁺ to NADH.
卡片 140
问题
Why measure an initial enzyme rate?
答案
Substrate depletion and product buildup have had less time to distort the rate.
卡片 141
问题
How can high temperature reduce enzyme activity?
答案
Heat can disrupt interactions that maintain the enzyme's functional shape.
卡片 142
问题
What is photosystem II's key contribution?
答案
It excites electrons and replaces them by oxidizing water.
卡片 143
问题
Where does the citric acid cycle occur in eukaryotes?
答案
In the mitochondrial matrix.
卡片 144
问题
What is oxidation?
答案
Loss of electrons, often accompanied by loss of hydrogen or gain of oxygen.
卡片 145
问题
Why does each enzyme have an optimal pH range?
答案
pH changes charges on amino-acid side chains and can alter binding or folding.
卡片 146
问题
What does the photosynthetic electron transport chain build?
答案
A proton gradient across the thylakoid membrane.
卡片 147
问题
What is the citric acid cycle's main energy role?
答案
It oxidizes acetyl groups and transfers electrons to NADH and FADH₂, making a small amount of ATP.
卡片 148
问题
In a photosynthesis experiment, why keep leaf area constant?
答案
Leaf area affects light capture and gas exchange, so changing it could confound the tested factor.
卡片 149
问题
How does a competitive inhibitor reduce enzyme activity?
答案
It competes with substrate for the active site.
卡片 150
问题
How does chloroplast ATP synthase make ATP?
答案
Protons flow from the thylakoid space to the stroma through ATP synthase, driving phosphorylation of ADP.
卡片 151
问题
Where is the respiratory electron transport chain located in eukaryotes?
答案
In the inner mitochondrial membrane.
卡片 152
问题
What is reduction?
答案
Gain of electrons, often accompanied by gain of hydrogen or loss of oxygen.
卡片 153
问题
How can extra substrate weaken competitive inhibition?
答案
More substrate increases the chance that substrate, rather than inhibitor, occupies the active site.
卡片 154
问题
What is photosystem I's key contribution?
答案
It re-energizes electrons used to reduce NADP⁺ to NADPH.
卡片 155
问题
What is oxygen's role in aerobic respiration?
答案
It is the final electron acceptor and combines with electrons and protons to form water.
卡片 156
问题
A respiration graph gets steeper after temperature rises. What does the slope show?
答案
A higher rate of the measured respiratory change, such as oxygen consumption per unit time.
卡片 157
问题
How does a noncompetitive inhibitor act?
答案
It binds away from the active site and changes enzyme activity, often by altering shape.
卡片 158
问题
What products of the light reactions feed the Calvin cycle?
答案
ATP and NADPH.
卡片 159
问题
How does electron transport create a proton gradient?
答案
Released electron energy pumps protons from the matrix to the intermembrane space.
卡片 160
问题
What do NADH and FADH₂ carry?
答案
High-energy electrons and associated hydrogen used in energy-transfer pathways.
卡片 161
问题
What is allosteric regulation?
答案
A regulator binds at one site and changes activity at another site on the protein.
卡片 162
问题
What does carbon fixation accomplish?
答案
It incorporates inorganic carbon dioxide into an organic molecule.
卡片 163
问题
What is oxidative phosphorylation?
答案
ATP production powered by electron transport and chemiosmosis.
卡片 164
问题
Why use multiple biological replicates in a rate experiment?
答案
They reveal natural variation and make the estimated treatment effect more reliable.
卡片 165
问题
What is fermentation's central purpose?
答案
It regenerates NAD⁺ so glycolysis can continue without an active electron transport chain.
卡片 166
问题
How does feedback inhibition control a pathway?
答案
A pathway's end product inhibits an earlier enzyme, reducing unnecessary production.
卡片 167
问题
What enzyme fixes carbon in the Calvin cycle?
答案
Rubisco.
卡片 168
问题
How does mitochondrial ATP synthase make ATP?
答案
Protons flow into the matrix through ATP synthase, driving ADP phosphorylation.
卡片 169
问题
Why do cells use stepwise electron transfers?
答案
They release energy in manageable increments that can be captured instead of lost mostly as heat.
卡片 170
问题
What is a cofactor?
答案
A nonprotein helper, often a metal ion or small organic coenzyme, required for some enzymes to function.
卡片 171
问题
What are the three broad phases of the Calvin cycle?
答案
Carbon fixation, reduction, and regeneration of the carbon-dioxide acceptor RuBP.
卡片 172
问题
How does lactic-acid fermentation regenerate NAD⁺?
答案
NADH reduces pyruvate to lactate, returning electrons to form NAD⁺.
卡片 173
问题
What is substrate-level phosphorylation?
答案
An enzyme transfers a phosphate directly from an intermediate to ADP.
卡片 174
问题
Error bars overlap broadly between two treatments. What is a careful conclusion?
答案
The graph alone does not show a clear difference; a suitable statistical analysis and design context are still needed.
卡片 175
问题
Why run an enzyme assay without enzyme?
答案
It measures the uncatalyzed background change and tests whether enzyme is required.
卡片 176
问题
How does alcoholic fermentation regenerate NAD⁺?
答案
Pyruvate loses carbon dioxide, and the remaining compound is reduced to ethanol as NADH becomes NAD⁺.
卡片 177
问题
What is G3P's role in photosynthesis?
答案
It is a three-carbon product that can leave the Calvin cycle and help build carbohydrates.
卡片 178
问题
Why are mitochondrial cristae useful?
答案
They increase inner-membrane area for electron transport chains and ATP synthase.
卡片 179
问题
What does phosphorylation often do to a molecule?
答案
It adds a phosphate group that can increase reactivity or alter a protein's shape and activity.
卡片 180
问题
A mutation lowers an enzyme's maximum rate but not substrate binding. What is a plausible effect?
答案
It may impair a catalytic step or reduce the number of functional enzyme molecules.
卡片 181
问题
Why must the Calvin cycle regenerate RuBP?
答案
RuBP is the carbon-dioxide acceptor needed for another turn of fixation.
卡片 182
问题
A chemical lowers oxygen use but not glycolysis. Which stage is most directly implicated?
答案
Aerobic electron transport or a process supplying it, because glycolysis itself does not consume oxygen.
卡片 183
问题
How would closed stomata affect photosynthesis?
答案
Carbon dioxide entry falls, which can limit carbon fixation even when light is available.
卡片 184
问题
A plant receives green light only. Predict its photosynthetic rate.
答案
It will usually be lower than under equally intense red or blue light because common chlorophylls absorb green poorly.
卡片 185
问题
Why does fermentation yield less ATP per glucose than aerobic respiration?
答案
It relies on glycolysis alone and leaves much of glucose's chemical energy in reduced end products.
卡片 186
问题
How does low ATP affect respiration pathway activity?
答案
It usually relieves inhibition of key enzymes, increasing fuel oxidation and ATP production.
卡片 187
问题
How can oxygen production estimate photosynthetic rate?
答案
Oxygen is a light-reaction product, so its production per unit time can serve as a rate proxy under controlled conditions.
卡片 188
问题
What happens to electron transport if oxygen is removed?
答案
The chain backs up because electrons lack a final acceptor; NADH accumulates and oxidative phosphorylation stops.
卡片 189
问题
Why does a light-response curve eventually level off?
答案
Another factor, such as carbon dioxide supply, temperature, or enzyme capacity, becomes limiting.
卡片 190
问题
An uncoupler lets protons cross the inner mitochondrial membrane. What happens?
答案
The gradient weakens, ATP production falls, and more energy is released as heat even if electron transport continues.
卡片 191
问题
What is direct-contact signaling?
答案
A membrane-bound molecule or cell junction communicates with an adjacent cell.
卡片 192
问题
What are the three broad stages of cell signaling?
答案
Reception, transduction, and response.
卡片 193
问题
How can a receptor mutation block a response even when ligand is present?
答案
The receptor may fail to bind ligand, change shape, or activate the first relay protein.
卡片 194
问题
What is negative feedback?
答案
A response reduces the original stimulus, helping stabilize a variable near a functional range.
卡片 195
问题
What happens during G1 phase?
答案
The cell grows, performs normal functions, and prepares for DNA replication.
卡片 196
问题
Cells show response values of 2, 7, and 18 after rising ligand doses. Describe the trend.
答案
The response increases with ligand dose across the tested range.
卡片 197
问题
What happens during reception?
答案
A ligand binds its receptor and changes the receptor's activity or shape.
卡片 198
问题
What is paracrine signaling?
答案
A cell releases a local regulator that acts on nearby target cells.
卡片 199
问题
What happens during S phase?
答案
DNA is replicated, producing sister chromatids for each chromosome.
卡片 200
问题
A response occurs without ligand. What pathway defect is plausible?
答案
A receptor or downstream relay protein may be constitutively active.
卡片 201
问题
What happens during signal transduction?
答案
Intracellular steps relay and often amplify information from the activated receptor.
卡片 202
问题
What is synaptic signaling?
答案
A neuron releases neurotransmitter across a short synaptic gap to a target cell.
卡片 203
问题
What happens during G2 phase?
答案
The cell grows, checks replicated DNA, and prepares the machinery for division.
卡片 204
问题
Why compare receptor-positive and receptor-negative cells?
答案
The comparison tests whether the receptor is necessary for the observed response.
卡片 205
问题
What counts as a cellular response?
答案
A change in gene expression, enzyme activity, ion flow, secretion, movement, division, or another cell behavior.
卡片 206
问题
How does insulin participate in negative feedback?
答案
High blood glucose promotes insulin release, which lowers blood glucose and reduces the original stimulus.
卡片 207
问题
What happens during mitosis?
答案
A eukaryotic nucleus separates duplicated chromosomes into two nuclei.
卡片 208
问题
What is endocrine signaling?
答案
Hormones travel through circulatory fluid to target cells that may be far away.
卡片 209
问题
What does a protein kinase do?
答案
It transfers a phosphate from ATP to a target protein.
卡片 210
问题
A drug blocks a kinase, and the final response disappears. What is supported?
答案
The kinase is required somewhere in that pathway under the tested conditions.
卡片 211
问题
What happens during cytokinesis?
答案
The cytoplasm divides to form separate daughter cells.
卡片 212
问题
How does glucagon participate in glucose homeostasis?
答案
Low blood glucose promotes glucagon release, which raises blood glucose toward the normal range.
卡片 213
问题
What does a protein phosphatase do?
答案
It removes a phosphate group from a target protein.
卡片 214
问题
What is a ligand?
答案
A signaling molecule that binds specifically to a receptor.
卡片 215
问题
What is the G1 checkpoint's broad role?
答案
It checks size, nutrients, growth signals, and DNA condition before replication.
卡片 216
问题
Why can't one inhibitor experiment prove a protein's exact pathway position?
答案
Off-target effects and indirect dependencies can produce the same outcome.
卡片 217
问题
Why are phosphorylation cascades reversible?
答案
Kinases add phosphates, while phosphatases remove them and reset pathway components.
卡片 218
问题
What is positive feedback?
答案
A response strengthens the initiating stimulus until a separate event stops the loop.
卡片 219
问题
What is the G2 checkpoint's broad role?
答案
It checks whether DNA replication is complete and damage is repaired before mitosis.
卡片 220
问题
Why don't all cells respond to the same hormone?
答案
Only cells with a compatible receptor and response machinery can respond.
卡片 221
问题
What is a second messenger?
答案
A small intracellular molecule or ion that relays a signal after receptor activation.
卡片 222
问题
How can rescue with an active downstream protein map a pathway?
答案
If the response returns despite an upstream block, the rescued protein likely acts downstream of that block.
卡片 223
问题
What does the spindle checkpoint verify?
答案
Every chromosome is correctly attached to spindle microtubules before sister chromatids separate.
卡片 224
问题
Why is blood clotting a positive-feedback process?
答案
Activated platelets recruit and activate more platelets until the break is sealed.
卡片 225
问题
Name two common second messengers.
答案
Cyclic AMP and calcium ions.
卡片 226
问题
A mutant receptor binds ligand but never becomes phosphorylated. Predict downstream signaling.
答案
It will likely fall or disappear if receptor phosphorylation is required to recruit relay proteins.
卡片 227
问题
How do cyclins regulate the cell cycle?
答案
Their concentrations rise and fall, activating cyclin-dependent kinases at specific stages.
卡片 228
问题
Why must DNA replicate before mitosis?
答案
Each daughter nucleus needs a complete copy of the genome.
卡片 229
问题
Where do receptors for many peptide hormones sit?
答案
In the plasma membrane, because these polar ligands do not readily cross the lipid bilayer.
卡片 230
问题
How can a signaling pathway amplify a weak signal?
答案
One activated component activates many downstream molecules at successive steps.
卡片 231
问题
What is the dependent variable in a ligand-dose experiment?
答案
The measured response, such as reporter activity, enzyme phosphorylation, or ion concentration.
卡片 232
问题
What do cyclin-dependent kinases do?
答案
When paired with cyclins, they phosphorylate targets that drive cell-cycle transitions.
卡片 233
问题
Why doesn't positive feedback usually maintain homeostasis by itself?
答案
It drives change away from the starting state and needs an external stop.
卡片 234
问题
What is a G protein's signaling role?
答案
It switches activity when bound to GTP and relays information from certain membrane receptors to effectors.
卡片 235
问题
How would you test whether calcium is required for a response?
答案
Block the calcium rise while keeping other conditions matched, then compare the response with a vehicle control.
卡片 236
问题
What is apoptosis?
答案
Programmed cell death that dismantles a cell in a controlled way.
卡片 237
问题
Where are receptors for many steroid hormones?
答案
Inside the cell, where lipid-soluble hormones can bind after crossing the membrane.
卡片 238
问题
How can an ion-channel receptor create a rapid response?
答案
Ligand binding opens or closes a pore, quickly changing ion movement and membrane conditions.
卡片 239
问题
Why test several ligand concentrations?
答案
A dose–response series can reveal sensitivity, saturation, and whether effects scale with ligand.
卡片 240
问题
Why is apoptosis useful in multicellular organisms?
答案
It removes damaged, infected, or unneeded cells with limited harm to neighbors.
卡片 241
问题
A thermostat-like pathway overshoots repeatedly. What defect is plausible?
答案
Delayed sensing or response can make negative feedback correct too late.
卡片 242
问题
How can an intracellular receptor affect gene expression?
答案
The ligand–receptor complex can act directly or indirectly as a transcription regulator.
卡片 243
问题
Cells lacking protein X divide despite DNA damage. Justify a checkpoint claim.
答案
Protein X likely supports a DNA-damage checkpoint because its absence links damage with continued division; rescue or pathway tests would strengthen the claim.
卡片 244
问题
What aligns at the metaphase plate?
答案
Duplicated chromosomes attached to spindle microtubules from opposite poles.
卡片 245
问题
How can failed checkpoints contribute to cancer?
答案
Cells with damage or abnormal signals can keep dividing instead of pausing or dying.
卡片 246
问题
How can gap junctions support communication?
答案
They connect neighboring animal-cell cytoplasms so small molecules and ions can pass directly.
卡片 247
问题
Why can the same ligand trigger different responses in two cell types?
答案
The cells can express different receptors, relay proteins, targets, or genes.
卡片 248
问题
Two pathways share one relay protein. What can happen if that protein is blocked?
答案
Both responses may weaken, showing pathway crosstalk or a shared component.
卡片 249
问题
During which mitotic stage do sister chromatids separate?
答案
Anaphase.
卡片 250
问题
What defines a malignant tumor?
答案
Its cells invade surrounding tissue and may spread to distant sites.
卡片 251
问题
How would loss of a feedback inhibitor affect a biosynthetic pathway?
答案
The pathway may stay active and overproduce its end product.
卡片 252
问题
What ends a signaling response?
答案
Ligand removal, receptor inactivation, GTP hydrolysis, messenger breakdown, or dephosphorylation can shut it down.
卡片 253
问题
A pathway diagram shows A activates B, and B inhibits C. Predict C after A activation.
答案
C activity should decrease, assuming the shown links are the relevant controlling interactions.
卡片 254
问题
A phosphatase that normally turns off an activated relay protein is inhibited. Predict the effect on that pathway.
答案
Phosphorylated targets may stay active longer, extending or strengthening the response.
卡片 255
问题
A drug prevents spindle formation. Where should the cycle stop?
答案
At the spindle checkpoint before anaphase, because chromosomes cannot attach correctly.
卡片 256
问题
What is the purpose of meiosis?
答案
It produces haploid cells and reshuffles inherited alleles for sexual reproduction.
卡片 257
问题
What is crossing over?
答案
Exchange of corresponding DNA segments between nonsister chromatids of homologous chromosomes.
卡片 258
问题
What does Mendel's law of segregation describe?
答案
An individual's two alleles for a gene separate into different gametes.
卡片 259
问题
Why do X-linked recessive traits often appear more frequently in XY individuals?
答案
They have only one X chromosome, so one recessive allele on it can determine the phenotype.
卡片 260
问题
What is incomplete dominance?
答案
The heterozygote has a phenotype intermediate between the two homozygotes.
卡片 261
问题
What does a chi-square goodness-of-fit test compare?
答案
Observed category counts with counts expected under a stated model.
卡片 262
问题
What is a homologous chromosome pair?
答案
Two chromosomes carrying the same gene locations, one inherited from each parent, possibly with different alleles.
卡片 263
问题
What does Mendel's law of independent assortment describe?
答案
Alleles of genes on different chromosomes, or far apart on one chromosome, assort independently during gamete formation.
卡片 264
问题
What is genetic linkage?
答案
Genes close together on the same chromosome tend to be inherited together.
卡片 265
问题
When does crossing over occur?
答案
During prophase I after homologs pair.
卡片 266
问题
How do sister chromatids differ from homologous chromosomes?
答案
Sister chromatids are replicated copies of one chromosome; homologs are the maternal and paternal versions of the same chromosome type.
卡片 267
问题
For Aa × Aa, what is the expected genotype ratio?
答案
1 AA : 2 Aa : 1 aa.
卡片 268
问题
How can linked genes produce recombinant offspring?
答案
Crossing over can exchange DNA between the gene locations.
卡片 269
问题
What is the usual null hypothesis for a Mendelian chi-square test?
答案
Any difference between observed and expected counts is due to chance sampling under the proposed inheritance model.
卡片 270
问题
What happens to homologous chromosomes in meiosis I?
答案
They pair and then separate into different cells.
卡片 271
问题
For Aa × Aa with complete dominance, what is the expected phenotype ratio?
答案
3 dominant phenotype : 1 recessive phenotype.
卡片 272
问题
How does crossing over increase variation?
答案
It creates chromosomes with new combinations of parental alleles.
卡片 273
问题
What does recombination frequency estimate?
答案
Relative distance between linked genes; higher frequency generally means greater separation, up to the 50% limit.
卡片 274
问题
What happens to sister chromatids in meiosis II?
答案
Their centromeres separate, and the chromatids move into different cells.
卡片 275
问题
What rule finds the probability of either of two mutually exclusive outcomes?
答案
Add their individual probabilities.
卡片 276
问题
What is codominance?
答案
Both alleles contribute distinct, detectable products or traits in the heterozygote.
卡片 277
问题
How is a chi-square contribution calculated for one category?
答案
Subtract expected from observed, square the difference, and divide by expected.
卡片 278
问题
When do homologous chromosomes pair as tetrads?
答案
During prophase I.
卡片 279
问题
What rule finds the probability that independent events both occur?
答案
Multiply their individual probabilities.
卡片 280
问题
What is independent assortment?
答案
Each homologous pair orients independently at metaphase I, producing many maternal–paternal chromosome combinations.
卡片 281
问题
Why can't recombination frequency exceed 50%?
答案
At 50%, recombinant and parental combinations are equally common and the genes behave as if unlinked.
卡片 282
问题
What aligns at the metaphase I plate?
答案
Homologous pairs, with each homolog attached toward an opposite pole.
卡片 283
问题
What is a test cross?
答案
Crossing an individual with a dominant phenotype to a homozygous recessive individual to infer the unknown genotype.
卡片 284
问题
How can one gene have multiple alleles?
答案
More than two allele forms can exist in the population, although one diploid individual carries at most two.
卡片 285
问题
How are total chi-square and category contributions related?
答案
Total chi-square is the sum of all category contributions.
卡片 286
问题
What separates during anaphase I?
答案
Homologous chromosomes; sister chromatids remain joined.
卡片 287
问题
How does random fertilization increase variation?
答案
Any one genetically varied gamete from one parent can fuse with any compatible gamete from the other.
卡片 288
问题
A test cross yields about half recessive offspring. What genotype is supported for the unknown parent?
答案
Heterozygous.
卡片 289
问题
What is nondisjunction?
答案
Failure of homologous chromosomes or sister chromatids to separate normally.
卡片 290
问题
What aligns during metaphase II?
答案
Individual duplicated chromosomes in each haploid cell.
卡片 291
问题
What is polygenic inheritance?
答案
Multiple genes contribute to one trait, often producing continuous phenotypic variation.
卡片 292
问题
For a simple goodness-of-fit test, how are degrees of freedom found?
答案
Number of categories minus one.
卡片 293
问题
Which meiotic events create variation before fertilization?
答案
Crossing over and independent assortment.
卡片 294
问题
How does ploidy change during meiosis?
答案
Homolog separation reduces diploid cells to haploid cells; meiosis II separates chromatids without another ploidy reduction.
卡片 295
问题
What pedigree pattern often suggests a recessive trait?
答案
Unaffected parents can have an affected child, if both parents carry the allele.
卡片 296
问题
How can meiotic nondisjunction affect gametes?
答案
It can produce gametes with an extra or missing chromosome.
卡片 297
问题
What is pleiotropy?
答案
One gene influences multiple phenotypic traits.
卡片 298
问题
Why is there no second DNA replication before meiosis II?
答案
The goal is to separate existing sister chromatids, not duplicate the genome again.
卡片 299
问题
What does a p-value below the chosen threshold support?
答案
Rejecting the null model because the observed deviation would be unlikely if that model were correct.
卡片 300
问题
Why are siblings genetically different even with the same parents?
答案
They inherit different allele combinations through crossing over, independent assortment, and random fertilization.
卡片 301
问题
Why do small families often deviate from expected Mendelian ratios?
答案
Probability ratios describe long-run expectations; random sampling variation is large with few offspring.
卡片 302
问题
A diploid cell has six chromosomes. How many chromosomes should each normal meiotic product have?
答案
Three.
卡片 303
问题
A trisomic zygote forms after fertilization. What meiotic error is a likely cause?
答案
Nondisjunction produced a gamete carrying an extra copy of that chromosome.
卡片 304
问题
Why can identical genotypes show different phenotypes?
答案
Environmental conditions and developmental variation can alter gene expression or trait development.
卡片 305
问题
What does failing to reject a genetic null hypothesis mean?
答案
The data do not show a significant departure from the model; they do not prove the model true.
卡片 306
问题
How do DNA and RNA sugars differ?
答案
DNA contains deoxyribose; RNA contains ribose.
卡片 307
问题
What does semiconservative DNA replication produce?
答案
Each daughter DNA molecule contains one original strand and one newly synthesized strand.
卡片 308
问题
What is transcription?
答案
Synthesis of RNA using DNA as a template.
卡片 309
问题
What is a point mutation?
答案
A change affecting one nucleotide pair.
卡片 310
问题
What is an operon?
答案
A group of prokaryotic genes controlled together and transcribed from one promoter.
卡片 311
问题
Why can muscle and nerve cells differ despite having the same genome?
答案
They express different sets and amounts of genes.
卡片 312
问题
What must a virus use from its host?
答案
Host resources and at least some host-cell machinery to copy or express its genome and produce new particles.
卡片 313
问题
What does PCR do?
答案
It amplifies a chosen DNA region through repeated cycles of strand separation, primer binding, and extension.
卡片 314
问题
What enzyme performs transcription?
答案
RNA polymerase.
卡片 315
问题
What does helicase do during replication?
答案
It unwinds the double helix and separates the template strands.
卡片 316
问题
How does a repressor reduce transcription?
答案
It binds regulatory DNA and blocks or hinders transcription machinery.
卡片 317
问题
What is a silent mutation?
答案
A nucleotide change that does not change the encoded amino acid.
卡片 318
问题
What does a promoter do?
答案
It marks where transcription machinery assembles and helps set the transcription start and direction.
卡片 319
问题
What does topoisomerase do ahead of a replication fork?
答案
It relieves twisting strain caused by DNA unwinding.
卡片 320
问题
How does an inducer affect an inducible operon?
答案
It disables the repressor or otherwise turns transcription on when the pathway's substrate is present.
卡片 321
问题
How do DNA and RNA bases differ?
答案
DNA uses thymine, while RNA uses uracil; both also use adenine, cytosine, and guanine.
卡片 322
问题
Which DNA strand does RNA polymerase read?
答案
The template strand, read 3′→5′ while RNA is built 5′→3′.
卡片 323
问题
Why is an RNA primer needed for DNA replication?
答案
DNA polymerase can extend an existing 3′ end but cannot start a strand from nothing.
卡片 324
问题
How does a corepressor affect a repressible operon?
答案
It activates a repressor, turning off genes when the pathway's end product is abundant.
卡片 325
问题
What is a missense mutation?
答案
A nucleotide change that substitutes one amino acid for another.
卡片 326
问题
How does an mRNA sequence relate to the coding DNA strand?
答案
It matches the coding strand except RNA has uracil in place of thymine.
卡片 327
问题
What does primase do?
答案
It builds short RNA primers.
卡片 328
问题
Why is the lac operon strongly expressed when lactose is present and glucose is scarce?
答案
Lactose relieves repression, while low glucose supports positive activation of transcription.
卡片 329
问题
Why are primers essential in PCR?
答案
They define the target boundaries and provide 3′ ends for DNA polymerase.
卡片 330
问题
What is the primary RNA transcript in a eukaryote?
答案
The initial RNA copy before processing.
卡片 331
问题
In which direction does DNA polymerase synthesize DNA?
答案
5′→3′ by adding nucleotides to a 3′ end.
卡片 332
问题
Why is the trp operon usually off when tryptophan is abundant?
答案
Tryptophan acts as a corepressor, enabling repression of biosynthetic genes.
卡片 333
问题
What holds complementary DNA bases together?
答案
Hydrogen bonds: adenine pairs with thymine, and cytosine pairs with guanine.
卡片 334
问题
What happens during RNA splicing?
答案
Introns are removed and exons are joined.
卡片 335
问题
Why is the leading strand synthesized continuously?
答案
Its template orientation lets polymerase follow the replication fork while synthesizing 5′→3′.
卡片 336
问题
How can histone acetylation affect transcription?
答案
It often loosens chromatin and makes DNA more accessible to transcription machinery.
卡片 337
问题
What is a nonsense mutation?
答案
A nucleotide change that creates a premature stop codon.
卡片 338
问题
What do the 5′ cap and poly-A tail help do?
答案
They protect eukaryotic mRNA and support export and translation.
卡片 339
问题
Why is the lagging strand synthesized in fragments?
答案
Its template orientation forces repeated 5′→3′ synthesis away from the moving fork.
卡片 340
问题
How can DNA methylation near a promoter affect transcription?
答案
It often reduces transcription by limiting access or recruiting repressive proteins.
卡片 341
问题
How does gel electrophoresis separate DNA fragments?
答案
An electric field pulls negatively charged DNA through a matrix; smaller fragments usually travel farther.
卡片 342
问题
How can alternative splicing increase protein diversity?
答案
Different exon combinations from one transcript can produce different mRNAs and polypeptides.
卡片 343
问题
What are Okazaki fragments?
答案
Short DNA segments made on the lagging strand.
卡片 344
问题
What does a transcription factor do?
答案
It binds regulatory DNA and helps increase or decrease transcription of specific genes.
卡片 345
问题
Why are DNA strands antiparallel?
答案
Their sugar–phosphate backbones run in opposite 5′→3′ directions.
卡片 346
问题
What is translation?
答案
Ribosomes use an mRNA codon sequence to build a polypeptide.
卡片 347
问题
What does DNA ligase do?
答案
It seals breaks in the sugar–phosphate backbone, joining DNA fragments.
卡片 348
问题
What is a frameshift mutation?
答案
An insertion or deletion not in multiples of three that shifts downstream codon grouping.
卡片 349
问题
How can an enhancer influence a distant promoter?
答案
DNA looping brings enhancer-bound activators near the transcription machinery.
卡片 350
问题
What does a codon specify?
答案
An amino acid or a translation stop signal.
卡片 351
问题
What do restriction enzymes do?
答案
They cut DNA at particular recognition sequences.
卡片 352
问题
What gives a nucleic-acid strand its 5′ and 3′ ends?
答案
The chemical groups on the sugar: a 5′ phosphate end and a 3′ hydroxyl end.
卡片 353
问题
How does proofreading improve replication accuracy?
答案
DNA polymerases detect and replace many incorrectly paired nucleotides.
卡片 354
问题
What does a tRNA anticodon do?
答案
It base-pairs with an mRNA codon so the attached amino acid is placed correctly.
卡片 355
问题
Why can a promoter mutation affect protein amount?
答案
It can change transcription-factor or RNA-polymerase binding and alter transcription rate.
卡片 356
问题
How can microRNA reduce gene expression?
答案
It base-pairs with target mRNA and promotes degradation or blocks translation.
卡片 357
问题
What maintains a differentiated cell's identity?
答案
Stable regulatory networks and chromatin states keep characteristic genes active or silent.
卡片 358
问题
What are the ribosome's broad roles?
答案
It positions mRNA and tRNAs and catalyzes peptide-bond formation.
卡片 359
问题
How can an RNA virus generate genetic variation quickly?
答案
Many viral RNA polymerases lack strong proofreading, so replication introduces mutations frequently.
卡片 360
问题
What can bacterial transformation demonstrate?
答案
Cells can take up external DNA and express a selectable or observable trait.
卡片 361
问题
Why is RNA usually more structurally varied than double-stranded DNA?
答案
A single RNA strand can fold back on itself through internal base pairing.
卡片 362
问题
What usually marks translation initiation?
答案
A start codon positioned with an initiator tRNA and ribosomal subunits.
卡片 363
问题
What problem do telomeres help solve?
答案
They protect chromosome ends from losing essential genes during repeated linear-DNA replication.
卡片 364
问题
Why can an intron splice-site mutation affect protein sequence?
答案
Incorrect splicing can remove exon sequence or retain intron sequence in the mature mRNA.
卡片 365
问题
How can protein degradation regulate a pathway quickly?
答案
Destroying a key protein lowers its activity without waiting for transcription to change.
卡片 366
问题
What happens at a stop codon?
答案
A release factor ends translation and frees the polypeptide.
卡片 367
问题
How can a signal change cell specialization?
答案
It can activate transcription factors that launch a new gene-expression program.
卡片 368
问题
What is a retrovirus's information flow?
答案
Viral RNA is reverse-transcribed into DNA, which can integrate into the host genome.
卡片 369
问题
What does DNA sequencing reveal directly?
答案
The order of nucleotides in the analyzed DNA; biological effects require further interpretation.
卡片 370
问题
Why is the genetic code called redundant?
答案
More than one codon can specify the same amino acid.
卡片 371
问题
Where does nucleotide sequence store information?
答案
The order of bases encodes information that can be copied, transcribed, or translated.
卡片 372
问题
Why is replication called bidirectional?
答案
Two forks usually move away from each origin in opposite directions.
卡片 373
问题
Why doesn't every DNA mutation change phenotype?
答案
It may occur outside a functional sequence, be silent, have a mild effect, or be masked by another allele or environment.
卡片 374
问题
How does a free ribosome's product usually differ from a rough-ER ribosome's product?
答案
Free ribosomes often make cytosolic proteins; ER-bound ribosomes make many secreted, membrane, and endomembrane proteins.
卡片 375
问题
Why can one signal coordinate many genes?
答案
A shared transcription regulator or signaling pathway can control multiple target promoters.
卡片 376
问题
Why does cell specialization depend on selective gene expression rather than gene loss?
答案
Most specialized cells retain the genome but use only the genes needed for their role.
卡片 377
问题
Why are viruses not described as independently living cells?
答案
They lack cellular metabolism and cannot reproduce without a host cell.
卡片 378
问题
A coding DNA triplet is 5′-ATG-3′. What is the matching mRNA codon?
答案
5′-AUG-3′.
卡片 379
问题
A PCR band is absent. Why isn't gene absence the only explanation?
答案
Poor DNA quality, wrong primers, inhibitors, or failed reaction conditions can also prevent amplification.
卡片 380
问题
Why can protein function require steps after translation?
答案
The polypeptide may need folding, cleavage, chemical modification, or assembly with other subunits.
卡片 381
问题
How do fossils support evolution?
答案
They document organisms and transitions through time, including appearance, change, and extinction.
卡片 382
问题
What conditions are required for natural selection?
答案
Individuals vary, some variation is heritable, and variants differ in survival or reproductive success in that environment.
卡片 383
问题
What is artificial selection?
答案
Humans choose which organisms reproduce based on desired heritable traits.
卡片 384
问题
What does an allele frequency measure?
答案
The fraction of all copies of a gene in a population represented by one allele.
卡片 385
问题
What does a node on a phylogenetic tree represent?
答案
A common ancestor where descendant lineages diverge.
卡片 386
问题
What is biological speciation?
答案
Evolution of reproductive isolation between populations, producing independently evolving lineages.
卡片 387
问题
What is extinction?
答案
Permanent loss of a species when no living members remain.
卡片 388
问题
A pesticide-treated population becomes mostly resistant. What evidence distinguishes selection from acclimation?
答案
Resistance should be heritable and increase across generations through differential reproduction, not just appear temporarily in exposed individuals.
卡片 389
问题
What changes during evolution by natural selection?
答案
Allele frequencies in a population across generations.
卡片 390
问题
For two alleles under Hardy–Weinberg notation, what does p + q equal?
答案
1.
卡片 391
问题
What is a clade?
答案
An ancestor and all of its descendants.
卡片 392
问题
What does homologous anatomy suggest?
答案
Similar underlying structures with different functions can indicate inheritance from a common ancestor.
卡片 393
问题
Do individual organisms evolve by natural selection?
答案
No. Individuals are selected; populations evolve as inherited variants change in frequency.
卡片 394
问题
Under Hardy–Weinberg equilibrium, what does p² represent?
答案
Expected frequency of one homozygous genotype.
卡片 395
问题
What is a shared derived character?
答案
A trait that evolved in a common ancestor and helps identify one of its descendant clades.
卡片 396
问题
What is mutation's evolutionary role?
答案
It creates new alleles, the ultimate source of new genetic variation.
卡片 397
问题
What is biological fitness?
答案
Relative contribution of viable, reproducing offspring to the next generation in a particular environment.
卡片 398
问题
Under Hardy–Weinberg equilibrium, what does 2pq represent?
答案
Expected frequency of heterozygotes.
卡片 399
问题
Which two tips on a tree are most closely related?
答案
Those sharing the most recent common ancestor, regardless of how close their names appear on the page.
卡片 400
问题
What is a vestigial structure?
答案
A reduced feature inherited from ancestors that has lost much or all of its earlier function.
卡片 401
问题
What is an adaptation?
答案
A heritable trait that became common because it improved fitness in past environments.
卡片 402
问题
Under Hardy–Weinberg equilibrium, what does q² represent?
答案
Expected frequency of the other homozygous genotype.
卡片 403
问题
How does recombination affect evolution?
答案
It reshuffles existing alleles into new combinations but does not itself create new alleles.
卡片 404
问题
Does rotating branches around a node change relationships?
答案
No. The branching pattern stays the same.
卡片 405
问题
Why isn't an adaptation always beneficial in every setting?
答案
Fitness effects depend on the environment and can involve tradeoffs.
卡片 406
问题
What are the Hardy–Weinberg assumptions?
答案
A very large population, random mating, no mutation, no migration, and no natural selection at the locus.
卡片 407
问题
How can embryological similarities support common ancestry?
答案
Shared developmental patterns can reflect inherited developmental genes and pathways.
卡片 408
问题
What is gene flow?
答案
Movement of alleles between populations through migration and reproduction.
卡片 409
问题
Does natural selection create needed mutations?
答案
No. Mutations arise without regard to need; selection changes the frequencies of their inherited effects.
卡片 410
问题
Why is Hardy–Weinberg equilibrium useful?
答案
It provides a null model for detecting or reasoning about evolutionary change.
卡片 411
问题
Does left-to-right tip order show evolutionary progress?
答案
No. Tip order is a drawing choice, not a ranking from primitive to advanced.
卡片 412
问题
What is allopatric speciation?
答案
Geographic separation reduces gene flow, allowing populations to diverge.
卡片 413
问题
What is directional selection?
答案
Selection favors one end of a phenotypic range, shifting the population mean.
卡片 414
问题
If q² = 0.09, what is q?
答案
0.30.
卡片 415
问题
Why is DNA sequence similarity evidence for relatedness?
答案
Related lineages inherit sequences from common ancestors, with differences accumulating over time.
卡片 416
问题
How does gene flow often affect differences between populations?
答案
It tends to make allele frequencies more similar.
卡片 417
问题
What is stabilizing selection?
答案
Selection favors intermediate phenotypes and removes extremes.
卡片 418
问题
If q = 0.30, what is p?
答案
0.70.
卡片 419
问题
What can branch length mean?
答案
Only what the figure defines—sometimes time or amount of change, and sometimes nothing quantitative.
卡片 420
问题
What is sympatric speciation?
答案
Reproductive isolation evolves without geographic separation, for example through polyploidy or strong niche and mating differences.
卡片 421
问题
What is disruptive selection?
答案
Selection favors both extremes over intermediate phenotypes.
卡片 422
问题
If p = 0.70 and q = 0.30, what is 2pq?
答案
0.42.
卡片 423
问题
Why include an untreated population in a selection experiment?
答案
It shows how allele or trait frequencies change without the selective treatment.
卡片 424
问题
Why is the nearly universal genetic code evidence of common ancestry?
答案
A deeply conserved information system is most simply explained by inheritance from early shared ancestors.
卡片 425
问题
What is balancing selection?
答案
Natural selection that maintains two or more alleles in a population, such as through heterozygote advantage or selection that varies across environments.
卡片 426
问题
What is genetic drift?
答案
Random change in allele frequencies caused by chance sampling across generations.
卡片 427
问题
If 16% of a Hardy–Weinberg population shows a recessive phenotype, what is q?
答案
0.40, because q is the square root of 0.16.
卡片 428
问题
Why use an outgroup in tree analysis?
答案
It helps infer which character states are ancestral versus derived in the focal group.
卡片 429
问题
What is a prezygotic barrier?
答案
A barrier that prevents mating or fertilization.
卡片 430
问题
Allele A rises from 0.20 to 0.45. Describe the evolutionary result.
答案
The population evolved at that locus because allele frequency changed.
卡片 431
问题
How does biogeography support evolution?
答案
Species distributions often match isolation history, dispersal, and descent from nearby ancestors.
卡片 432
问题
What is sexual selection?
答案
Differences in mating success drive changes in traits that affect mate attraction or competition.
卡片 433
问题
When is genetic drift strongest?
答案
In small populations.
卡片 434
问题
Why can a rare recessive allele persist?
答案
Selection cannot remove copies hidden in heterozygotes as efficiently as copies expressed in homozygotes.
卡片 435
问题
How can molecular data revise a phylogenetic tree?
答案
Sequence comparisons can reveal relationships not obvious from morphology or distinguish convergence from homology.
卡片 436
问题
What is a postzygotic barrier?
答案
A barrier that reduces hybrid survival, fertility, or later-generation success after fertilization.
卡片 437
问题
How can rapid environmental change increase extinction risk?
答案
Populations may lack enough suitable variation or time to adapt or move.
卡片 438
问题
A small island population loses alleles after a storm. Which mechanism is most direct?
答案
Genetic drift through a bottleneck.
卡片 439
问题
What is convergent evolution?
答案
Unrelated lineages independently evolve similar traits under similar selective pressures.
卡片 440
问题
Why can antibiotic resistance spread rapidly?
答案
Treatment strongly favors resistant variants already present or newly introduced, which leave more descendants.
卡片 441
问题
What is a bottleneck effect?
答案
A sharp population reduction leaves a random, often less diverse sample of the original gene pool.
卡片 442
问题
How do genotype counts yield allele frequency?
答案
Count two copies from each homozygote and one from each heterozygote, then divide by twice the number of diploid individuals.
卡片 443
问题
What is maximum parsimony in tree building?
答案
Preferring the tree that requires the fewest evolutionary changes under the model.
卡片 444
问题
How can different breeding times isolate populations?
答案
Temporal isolation prevents individuals from mating even when they share a location.
卡片 445
问题
Why can mass extinctions reshape evolution?
答案
They remove many lineages and open ecological opportunities for survivors.
卡片 446
问题
Two similar traits evolved on distant tree branches. What explanation should be evaluated?
答案
Convergent evolution under similar selection, alongside the possibility of an incorrect tree or unrecognized homology.
卡片 447
问题
Why are analogous structures weak evidence of close ancestry?
答案
Their similar function may have evolved independently rather than from the same ancestral structure.
卡片 448
问题
Why doesn't natural selection produce perfection?
答案
It works with existing variation under tradeoffs, historical constraints, chance, and changing environments.
卡片 449
问题
What is a founder effect?
答案
A new population starts from a small, nonrepresentative sample of a source population.
卡片 450
问题
Observed genotypes differ from Hardy–Weinberg expectations. What is supported?
答案
At least one model assumption may not hold, or sampling error may matter; the deviation alone does not identify the cause.
卡片 451
问题
Why is a phylogenetic tree a hypothesis?
答案
It is an evidence-based reconstruction that can change when new data or methods appear.
卡片 452
问题
How can behavioral differences cause isolation?
答案
Different courtship signals reduce mating between populations.
卡片 453
问题
What evidence can test origin-of-life hypotheses?
答案
Chemistry experiments, geological records, molecular comparisons, and plausible self-replicating or membrane-forming systems.
卡片 454
问题
How should fitness be compared in an experiment?
答案
Measure relative reproductive contribution, such as viable offspring, under the same environmental conditions.
卡片 455
问题
What does the fossil record not provide?
答案
A complete sample of every organism or every transitional population.
卡片 456
问题
How can a neutral trait change in frequency?
答案
Genetic drift can shift it by chance, especially in small populations.
卡片 457
问题
How can drift reduce adaptive potential?
答案
It can remove alleles and lower genetic diversity needed under future environmental change.
卡片 458
问题
Why does a large population support Hardy–Weinberg stability?
答案
Chance sampling has less effect on allele frequencies, reducing drift.
卡片 459
问题
If A and B share a more recent node with each other than either shares with C, what does that mean?
答案
A and B are sister taxa and share a more recent common ancestor with each other than with C.
卡片 460
问题
What is adaptive radiation?
答案
Rapid diversification of one ancestral lineage into species using different ecological roles.
卡片 461
问题
What can experiments producing organic molecules from simple chemicals show?
答案
That some building blocks can form under modeled conditions; they do not recreate or prove the exact origin of life.
卡片 462
问题
A correlation links beak size with survival. Why isn't causation settled?
答案
Other traits or habitats may covary with beak size; controlled or multivariable evidence is needed.
卡片 463
问题
Why does agreement among fossils, anatomy, and molecules strengthen an evolutionary claim?
答案
Independent evidence types pointing to the same history make alternative explanations less plausible.
卡片 464
问题
A drought favors deeper beaks. What must be measured to show selection?
答案
Heritable beak variation and differences in survival or reproduction linked to beak depth.
卡片 465
问题
Why can artificial selection produce unintended traits?
答案
Selected genes may be linked to other alleles, and inbreeding can expose harmful recessive alleles.
卡片 466
问题
What data are needed to test Hardy–Weinberg genotype expectations?
答案
Population genotype counts or reliable genotype frequencies for the locus.
卡片 467
问题
Why doesn't one living species count as the ancestor of another on a typical tree?
答案
Living tips represent lineages that have both evolved since their shared ancestral lineage.
卡片 468
问题
Why can reduced gene flow accelerate divergence?
答案
Populations retain separate mutations, drift independently, and respond to different selective pressures.
卡片 469
问题
Why are ribozymes relevant to early-life hypotheses?
答案
RNA can both store information and catalyze reactions, offering a possible bridge before modern DNA–protein systems.
卡片 470
问题
What makes an evolutionary argument strong?
答案
A clear claim, relevant population-level evidence, and reasoning that connects inheritance and differential reproduction to the observed change.
卡片 471
问题
How can a directional response help an organism?
答案
Moving toward resources or away from hazards can improve survival and reproduction.
卡片 472
问题
What is a trophic level?
答案
A feeding position in the flow of energy through an ecosystem.
卡片 473
问题
What processes move carbon into and out of biological molecules?
答案
Photosynthesis fixes carbon; respiration, decomposition, and combustion release carbon dioxide.
卡片 474
问题
What does exponential population growth assume?
答案
Resources are effectively unlimited and the per-capita growth rate stays constant.
卡片 475
问题
What is a density-dependent limiting factor?
答案
Its effect strengthens as population density rises, such as competition, disease, or predation.
卡片 476
问题
What is a keystone species?
答案
A species whose ecological effect is disproportionately large relative to its abundance.
卡片 477
问题
What are three levels of biodiversity?
答案
Genetic diversity, species diversity, and ecosystem diversity.
卡片 478
问题
What is the independent variable in a fertilizer–algae experiment?
答案
The fertilizer amount or nutrient concentration deliberately changed.
卡片 479
问题
What shape represents exponential growth over time?
答案
A J-shaped curve.
卡片 480
问题
What do primary producers do?
答案
They capture external energy and build organic molecules from inorganic carbon.
卡片 481
问题
What is a density-independent limiting factor?
答案
Its effect is not primarily set by population density, such as a severe freeze or wildfire.
卡片 482
问题
Why is nitrogen fixation necessary?
答案
Most organisms cannot use atmospheric nitrogen gas directly, so it must be converted to biologically available compounds.
卡片 483
问题
What does logistic growth add to the exponential model?
答案
Growth slows as population size approaches carrying capacity.
卡片 484
问题
What is gross primary productivity?
答案
The total rate at which producers capture energy in organic matter.
卡片 485
问题
What is competition?
答案
An interaction in which organisms using the same limited resource reduce one another's access or fitness.
卡片 486
问题
What is ecological succession?
答案
Change in community composition after new habitat forms or a disturbance alters an existing community.
卡片 487
问题
What shape represents ideal logistic growth?
答案
An S-shaped curve.
卡片 488
问题
What is net primary productivity?
答案
Gross primary productivity minus producers' respiratory energy use.
卡片 489
问题
Why does genetic diversity matter for conservation?
答案
It increases the range of inherited responses available under disease or environmental change.
卡片 490
问题
What organisms perform much biological nitrogen fixation?
答案
Certain prokaryotes, including free-living and symbiotic bacteria.
卡片 491
问题
What is carrying capacity?
答案
The population size an environment can sustain over time under current conditions.
卡片 492
问题
Why is net primary productivity important to consumers?
答案
It is the producer biomass and energy available for growth and the next trophic levels.
卡片 493
问题
What is competitive exclusion?
答案
Species with identical limiting-resource niches cannot coexist indefinitely under stable conditions.
卡片 494
问题
How do primary and secondary succession differ?
答案
Primary succession begins without developed soil; secondary succession begins where soil remains.
卡片 495
问题
Why can carrying capacity change?
答案
Resources, habitat, climate, competitors, disease, and disturbance can change.
卡片 496
问题
Why does available energy decline up a food chain?
答案
Organisms use much energy for metabolism and lose it as heat and waste rather than storing it as biomass.
卡片 497
问题
What is an ecosystem service?
答案
A benefit people receive from ecosystems, such as pollination, water purification, soil formation, or climate regulation.
卡片 498
问题
What does nitrification do?
答案
Microbes oxidize ammonium to nitrite and then nitrate.
卡片 499
问题
What does per-capita growth rate measure?
答案
Population change per individual per unit time.
卡片 500
问题
What is ecological efficiency?
答案
The percentage of energy or production transferred from one trophic level to the next.
卡片 501
问题
What is resource partitioning?
答案
Competing species use different resources, places, or times, reducing direct overlap.
卡片 502
问题
What is resilience in an ecosystem?
答案
The ability to recover structure or function after disturbance.
卡片 503
问题
How is population growth estimated from births, deaths, immigration, and emigration?
答案
Births + immigration − deaths − emigration.
卡片 504
问题
If producers store 10,000 kJ and primary consumers receive 10%, how much do they receive?
答案
1,000 kJ.
卡片 505
问题
How does habitat fragmentation affect populations?
答案
It shrinks and isolates habitat, reducing movement and gene flow while increasing edge effects.
卡片 506
问题
Why sample several sites within each habitat?
答案
Replication captures spatial variation and reduces the chance that one unusual site drives the result.
卡片 507
问题
A population grows from 200 to 230 in one year. What is its percent growth?
答案
15%, because the increase of 30 divided by 200 is 0.15.
卡片 508
问题
What is a circadian rhythm?
答案
An internal roughly 24-hour cycle that environmental cues can reset.
卡片 509
问题
Why are food webs more realistic than simple food chains?
答案
Most species eat or are eaten by multiple species, creating connected pathways.
卡片 510
问题
What does denitrification do?
答案
Microbes convert nitrate to nitrogen gases, returning nitrogen to the atmosphere.
卡片 511
问题
What characterizes an r-selected life-history strategy?
答案
Many offspring, early reproduction, and relatively low investment per offspring in variable environments.
卡片 512
问题
What is mutualism?
答案
An interaction that benefits both species.
卡片 513
问题
What is resistance in an ecosystem?
答案
The ability to remain relatively unchanged during disturbance.
卡片 514
问题
How can climate change shift species ranges?
答案
Organisms track suitable temperature, moisture, seasons, or interacting species when movement is possible.
卡片 515
问题
What characterizes a K-selected life-history strategy?
答案
Fewer offspring, later reproduction, and higher investment per offspring near carrying capacity.
卡片 516
问题
A population curve levels near 800. What does the model suggest?
答案
About 800 is the carrying capacity under those measured conditions, not a permanent universal value.
卡片 517
问题
How can seasonal cues affect reproduction?
答案
Changes such as day length can trigger hormonal and behavioral shifts timed to favorable conditions.
卡片 518
问题
What role do decomposers play?
答案
They break down dead material and waste, returning nutrients to forms other organisms can use.
卡片 519
问题
Why can phosphorus limit ecosystems?
答案
It is essential but often released slowly from rocks and lacks a large atmospheric gas phase.
卡片 520
问题
What does a Type I survivorship curve show?
答案
High survival through early and middle life, followed by a steep decline at older ages.
卡片 521
问题
What is commensalism?
答案
One species benefits while the other has no clear benefit or harm.
卡片 522
问题
Why can diversity improve ecosystem stability?
答案
Multiple species or response types can keep functions going when one component declines.
卡片 523
问题
Why can overharvesting destabilize a population?
答案
Removal faster than replacement lowers abundance and can alter age structure or genetic diversity.
卡片 524
问题
Predator and prey peaks alternate over time. What can the graph establish?
答案
Their abundances covary with a lag; the graph alone cannot prove the predator caused every prey change.
卡片 525
问题
What is acclimation?
答案
A reversible phenotypic adjustment by an individual to an environmental change.
卡片 526
问题
Does energy cycle through an ecosystem?
答案
No. Energy flows through and is ultimately dissipated as heat; matter cycles.
卡片 527
问题
How does the water cycle connect ecosystems?
答案
Evaporation, transpiration, condensation, precipitation, runoff, and infiltration move water and dissolved materials.
卡片 528
问题
What does a Type II survivorship curve show?
答案
A roughly constant mortality risk across ages.
卡片 529
问题
What is parasitism?
答案
A parasite benefits while reducing its host's fitness.
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问题
What is an invasive species?
答案
A nonnative species that spreads and causes ecological, economic, or human-health harm.
卡片 531
问题
How can a wildlife corridor help fragmented populations?
答案
It supports movement, recolonization, and gene flow between habitat patches.
卡片 532
问题
How should biodiversity be compared when sample effort differs?
答案
Standardize sampling effort or use a method that accounts for unequal effort before comparing.
卡片 533
问题
How does acclimation differ from adaptation?
答案
Acclimation occurs within an individual; adaptation is an inherited population change across generations.
卡片 534
问题
How can removal of a top predator affect lower trophic levels?
答案
It can trigger a trophic cascade by changing prey abundance and the organisms prey consume.
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问题
Why can extra fertilizer cause low oxygen in water?
答案
Nutrient enrichment drives algal growth; decomposition then consumes dissolved oxygen.
卡片 536
问题
What does a Type III survivorship curve show?
答案
High early mortality with much better survival among those reaching later stages.
卡片 537
问题
How can predation maintain diversity?
答案
A predator can prevent one strong competitor from dominating the community.
卡片 538
问题
How can disturbance increase or decrease diversity?
答案
Its effect depends on frequency and intensity; it may create habitat variety or eliminate sensitive species.
卡片 539
问题
Why protect multiple habitats rather than one small reserve?
答案
Different habitats, disturbances, and climate trajectories preserve more species and ecological options.
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问题
A restoration site gains species but not nutrient cycling. How should success be evaluated?
答案
Use both composition and ecosystem-function measures; one metric alone gives an incomplete result.
