ATI TEAS 7 Science Flashcards: A&P, Biology, Chemistry & Scientific Reasoning
Practice 446 original ATI TEAS 7 Science recall and mini-scenario cards across A&P, biology, chemistry, and scientific reasoning.
Sobre este mazo
Build the core Science knowledge and reasoning used for ATI TEAS 7 with 446 independently authored flashcards.
What this deck practices
- Structure or concept → function: body systems, cells, molecules, atoms, solutions, and experimental parts.
- Function, outcome, or evidence → concept: selective reverse recall when recognizing the name matters in practice.
- Cause or condition → effect: physiology, chemical changes, reaction conditions, inheritance, and experimental predictions.
- Process and order: circulation, ventilation, digestion, urine formation, gene expression, cell division, and scientific investigations.
- Application: short calculations, comparisons, data interpretations, and original mini-scenarios.
The deck does not mechanically reverse every fact. It excludes multiple-choice distractors, exhaustive anatomy lists, obscure chemical nomenclature, advanced pathophysiology, pharmacology, and nursing-school procedures because those mappings do not improve entry-level TEAS Science recall.
The sequence introduces prerequisites before dependent ideas: anatomical language before body systems, cells before genetics, atoms before reactions, and measurement before experimental design. Related forward and reverse variants are separated so one card does not immediately reveal another.
Coverage follows the four Science areas and relative emphasis in ATI's public ATI TEAS 7 content outline: Human Anatomy and Physiology, Biology, Chemistry, and Scientific Reasoning. The public outline defines scope only. Questions, answers, explanations, examples, and ordering were independently authored from common scientific knowledge checked against open educational and official public sources.
No exam question, mark scheme, paid ATI flashcard, test-bank item, or curriculum text was copied. This is an independent, unofficial educational deck by Flashcards Open Source App. ATI and TEAS are marks of Assessment Technologies Institute, L.L.C.; this deck is not affiliated with, endorsed by, or produced by ATI. See ATI's official exam details for current requirements.
Tarjetas de este mazo
Tarjeta 1
Pregunta
What posture defines the standard anatomical position?
Respuesta
Standing upright, facing forward, with arms at the sides and palms forward. The feet point forward, giving anatomy a consistent reference position.
Tarjeta 2
Pregunta
In anatomical language, what does superior mean?
Respuesta
Toward the head or above another structure. Inferior means toward the feet or below.
Tarjeta 3
Pregunta
Which anatomical plane divides the body into left and right portions?
Respuesta
The sagittal plane. A midsagittal plane divides the body into equal left and right halves.
Tarjeta 4
Pregunta
Why does the body use feedback mechanisms?
Respuesta
To regulate internal conditions. Feedback compares a condition with a set range and triggers responses that adjust it.
Tarjeta 5
Pregunta
What is the order of structural organization from simplest to most complex?
Respuesta
Chemical, cellular, tissue, organ, organ system, organism. Each level builds on interactions at the preceding level.
Tarjeta 6
Pregunta
What does anterior mean in human anatomy?
Respuesta
Toward the front of the body. Posterior means toward the back.
Tarjeta 7
Pregunta
Which plane divides the body into upper and lower portions?
Respuesta
The transverse plane. It is also called the horizontal plane.
Tarjeta 8
Pregunta
What is homeostasis?
Respuesta
The maintenance of a relatively stable internal environment. It is dynamic rather than perfectly unchanging.
Tarjeta 9
Pregunta
Which major body cavity contains the brain and spinal cord?
Respuesta
The dorsal body cavity. Its cranial cavity holds the brain, and its vertebral cavity holds the spinal cord.
Tarjeta 10
Pregunta
What does medial mean in anatomical language?
Respuesta
Toward the body's midline. Lateral means farther from the midline.
Tarjeta 11
Pregunta
A rise in body temperature triggers sweating. What control pattern is this?
Respuesta
Negative feedback. The response opposes the original temperature change and moves the body toward its normal range.
Tarjeta 12
Pregunta
Which anatomical plane divides the body into front and back portions?
Respuesta
The frontal, or coronal, plane. It separates anterior from posterior portions.
Tarjeta 13
Pregunta
Which major body cavity contains the thoracic and abdominopelvic cavities?
Respuesta
The ventral body cavity. The diaphragm separates its thoracic and abdominopelvic portions.
Tarjeta 14
Pregunta
What does proximal mean when describing a limb?
Respuesta
Closer to the limb's point of attachment. Distal means farther from that point.
Tarjeta 15
Pregunta
How does positive feedback differ from negative feedback?
Respuesta
Positive feedback amplifies the initial change. Negative feedback opposes a change; positive feedback continues until a stopping event occurs.
Tarjeta 16
Pregunta
Which tissue type covers surfaces and lines body cavities?
Respuesta
Epithelial tissue. It also forms many glands and often serves protective, absorptive, or secretory roles.
Tarjeta 17
Pregunta
Which tissue type mainly supports, binds, and protects other tissues?
Respuesta
Connective tissue. Its cells are typically separated by an extracellular matrix.
Tarjeta 18
Pregunta
What shared property lets muscle tissue produce movement?
Respuesta
Contractility. Muscle cells shorten or develop tension in response to stimulation.
Tarjeta 19
Pregunta
Which tissue type rapidly communicates by electrical signals?
Respuesta
Nervous tissue. Neurons transmit signals, while supporting cells help maintain their environment.
Tarjeta 20
Pregunta
Why are tightly packed epithelial cells well suited for barriers?
Respuesta
They leave little space between cells. This continuous arrangement limits passage across a surface.
Tarjeta 21
Pregunta
What distinguishes connective tissue from epithelial tissue?
Respuesta
Connective tissue usually has abundant extracellular matrix. Epithelial cells are more tightly packed.
Tarjeta 22
Pregunta
What are the four basic human tissue types?
Respuesta
Epithelial, connective, muscle, and nervous tissue. Organs contain two or more tissue types working together.
Tarjeta 23
Pregunta
What makes a structure an organ rather than a tissue?
Respuesta
An organ combines multiple tissue types for a specific function. A tissue is a group of similar cells and matrix performing related work.
Tarjeta 24
Pregunta
What are the skeletal system's main functions?
Respuesta
Support, protection, movement, mineral storage, blood-cell production, and fat storage. Bones also provide levers for muscles.
Tarjeta 25
Pregunta
What belongs to the axial skeleton?
Respuesta
The skull, vertebral column, and thoracic cage. These structures form the body's central axis.
Tarjeta 26
Pregunta
How do compact and spongy bone differ?
Respuesta
Compact bone is dense; spongy bone has a lattice of trabeculae. Both are organized living bone tissue.
Tarjeta 27
Pregunta
What is a joint?
Respuesta
A place where two or more bones meet. Joint structure determines how much movement is possible.
Tarjeta 28
Pregunta
Which bone cell builds new bone matrix?
Respuesta
An osteoblast. Osteoclasts break down bone, while osteocytes maintain mature bone tissue.
Tarjeta 29
Pregunta
What belongs to the appendicular skeleton?
Respuesta
The limbs plus the shoulder and pelvic girdles. It attaches the limbs to the axial skeleton.
Tarjeta 30
Pregunta
What is the main role of red bone marrow?
Respuesta
Blood-cell production. This process is called hematopoiesis.
Tarjeta 31
Pregunta
Which joint class allows the greatest range of motion?
Respuesta
A synovial joint. A fluid-filled joint cavity reduces friction between articulating surfaces.
Tarjeta 32
Pregunta
Which bone cell breaks down bone matrix?
Respuesta
An osteoclast. Bone resorption helps remodeling and mineral balance.
Tarjeta 33
Pregunta
What does a ligament connect?
Respuesta
Bone to bone. A tendon connects muscle to bone.
Tarjeta 34
Pregunta
What is the shaft of a long bone called?
Respuesta
The diaphysis. The enlarged ends are the epiphyses.
Tarjeta 35
Pregunta
Why is bone important to blood-calcium balance?
Respuesta
Bone stores calcium and can release or absorb it during remodeling. Hormones regulate this exchange.
Tarjeta 36
Pregunta
What is stored mainly in yellow bone marrow?
Respuesta
Fat. It serves as an energy reserve.
Tarjeta 37
Pregunta
What does articular cartilage do at a synovial joint?
Respuesta
It reduces friction and absorbs shock. It covers the ends of articulating bones.
Tarjeta 38
Pregunta
Why must a broken bone receive a blood supply during healing?
Respuesta
Repairing cells need oxygen and nutrients. Restored blood vessels support fracture healing.
Tarjeta 39
Pregunta
What is bone remodeling?
Respuesta
Continuous removal and replacement of bone tissue. It repairs microdamage and helps bones adapt to stress.
Tarjeta 40
Pregunta
Which muscle tissue is usually under voluntary control?
Respuesta
Skeletal muscle. Most skeletal muscles move the skeleton, while some, such as facial muscles, insert into skin or other soft tissue.
Tarjeta 41
Pregunta
What is a sarcomere?
Respuesta
The basic contractile unit of striated muscle. It lies between two Z discs.
Tarjeta 42
Pregunta
What does a tendon connect?
Respuesta
Muscle to bone. It transmits muscle force to the skeleton.
Tarjeta 43
Pregunta
Which proteins slide past one another during muscle contraction?
Respuesta
Actin and myosin. Their interaction shortens sarcomeres without shortening the filaments themselves.
Tarjeta 44
Pregunta
Where is smooth muscle commonly found?
Respuesta
In the walls of hollow organs and blood vessels. Its contractions are generally involuntary.
Tarjeta 45
Pregunta
What ion exposes binding sites needed for skeletal muscle contraction?
Respuesta
Calcium. Its release inside the muscle fiber allows actin and myosin interaction.
Tarjeta 46
Pregunta
How do antagonistic muscle pairs move a joint?
Respuesta
One muscle contracts while the opposing muscle relaxes. Reversing their roles moves the joint in the opposite direction.
Tarjeta 47
Pregunta
Why does muscle contraction require ATP?
Respuesta
ATP powers cross-bridge cycling and ion pumps. It is also needed for myosin to detach from actin.
Tarjeta 48
Pregunta
Which muscle tissue makes up the heart wall?
Respuesta
Cardiac muscle. It is striated, involuntary, and connected for coordinated pumping.
Tarjeta 49
Pregunta
During a typical muscle contraction, which attachment moves more: origin or insertion?
Respuesta
The insertion. The origin is generally the more fixed attachment.
Tarjeta 50
Pregunta
Which type of neuron sends the signal that initiates skeletal-muscle contraction?
Respuesta
A somatic motor neuron. It releases acetylcholine at the neuromuscular junction, triggering an action potential in the muscle fiber.
Tarjeta 51
Pregunta
What is muscle tone?
Respuesta
Continuous low-level muscle tension. It helps maintain posture and readiness without producing a large movement.
Tarjeta 52
Pregunta
How does skeletal muscle help regulate body temperature?
Respuesta
Contraction releases heat. Shivering increases rapid contractions when the body is cold.
Tarjeta 53
Pregunta
What are the three muscle tissue types?
Respuesta
Skeletal, cardiac, and smooth muscle. They differ in location, structure, and control.
Tarjeta 54
Pregunta
What is a neuron's main function?
Respuesta
To receive, process, and transmit information. Neurons use electrical signals and chemical messengers.
Tarjeta 55
Pregunta
What structures make up the central nervous system?
Respuesta
The brain and spinal cord. They integrate information and coordinate responses.
Tarjeta 56
Pregunta
Which part of a neuron usually receives incoming signals?
Respuesta
The dendrites. The cell body integrates much of that input.
Tarjeta 57
Pregunta
What does the peripheral nervous system include?
Respuesta
Nerves and ganglia outside the brain and spinal cord. It links the central nervous system with the rest of the body.
Tarjeta 58
Pregunta
Which neuron structure carries an impulse away from the cell body?
Respuesta
The axon. Its terminals communicate with another cell.
Tarjeta 59
Pregunta
Which nervous-system division controls skeletal muscles voluntarily?
Respuesta
The somatic nervous system. It also carries sensory information from skin, muscles, and joints.
Tarjeta 60
Pregunta
What is a synapse?
Respuesta
A junction where one neuron communicates with another cell. Chemical synapses use neurotransmitters across a small gap.
Tarjeta 61
Pregunta
Which nervous-system division regulates organs and glands without conscious control?
Respuesta
The autonomic nervous system. It includes sympathetic and parasympathetic divisions.
Tarjeta 62
Pregunta
How does myelin affect nerve signaling?
Respuesta
It speeds impulse conduction along an axon. Myelin insulates segments of the axon.
Tarjeta 63
Pregunta
Which autonomic division prepares the body for acute activity?
Respuesta
The sympathetic division. It generally increases alertness and supports a fight-or-flight response.
Tarjeta 64
Pregunta
What is a reflex?
Respuesta
A rapid, predictable response to a stimulus. A reflex pathway can act before conscious awareness.
Tarjeta 65
Pregunta
Which autonomic division supports rest, digestion, and energy conservation?
Respuesta
The parasympathetic division. It generally promotes routine maintenance functions.
Tarjeta 66
Pregunta
Which brain region is most associated with conscious thought and voluntary movement?
Respuesta
The cerebrum. Its cortex also processes much sensory information.
Tarjeta 67
Pregunta
Which brain region fine-tunes balance and coordinated movement?
Respuesta
The cerebellum. It compares intended movement with sensory feedback.
Tarjeta 68
Pregunta
Which brain region controls vital automatic functions such as breathing and heart rate?
Respuesta
The brainstem. It also connects higher brain regions with the spinal cord.
Tarjeta 69
Pregunta
How do sensory and motor neurons differ?
Respuesta
Sensory neurons carry information toward the CNS; motor neurons carry commands away. Interneurons connect and process signals within the CNS.
Tarjeta 70
Pregunta
What does a sensory receptor do?
Respuesta
It converts a stimulus into a neural signal. Different receptors respond best to particular forms of energy or chemicals.
Tarjeta 71
Pregunta
What is a hormone?
Respuesta
A chemical messenger released into body fluids to affect target cells. A target responds only if it has the appropriate receptor.
Tarjeta 72
Pregunta
Why is the pituitary gland often called a master gland?
Respuesta
Several pituitary hormones regulate other endocrine glands. The hypothalamus controls much of pituitary activity.
Tarjeta 73
Pregunta
Why can one hormone affect some cells but not others?
Respuesta
Only target cells have the matching receptor. Receptor binding starts the cell's response.
Tarjeta 74
Pregunta
Which gland produces hormones that broadly increase metabolic activity?
Respuesta
The thyroid gland. Thyroid hormones influence energy use and development.
Tarjeta 75
Pregunta
What is insulin's main effect on blood glucose?
Respuesta
It lowers blood glucose. Insulin promotes glucose uptake and storage after a meal.
Tarjeta 76
Pregunta
Which glands release a hormone that raises blood calcium?
Respuesta
The parathyroid glands. Parathyroid hormone acts on bone, kidneys, and vitamin D pathways.
Tarjeta 77
Pregunta
Which adrenal region releases epinephrine during acute stress?
Respuesta
The adrenal medulla. Its hormones reinforce sympathetic nervous-system effects.
Tarjeta 78
Pregunta
Which organ has both endocrine and digestive functions?
Respuesta
The pancreas. Its islets release hormones, while other cells release digestive enzymes.
Tarjeta 79
Pregunta
What is glucagon's main effect on blood glucose?
Respuesta
It raises blood glucose. It promotes release of stored glucose during fasting.
Tarjeta 80
Pregunta
Rising thyroid hormone reduces its own upstream stimulation. What pattern is this?
Respuesta
Negative feedback. The final hormone limits further release along the control pathway.
Tarjeta 81
Pregunta
Which adrenal region produces steroid hormones such as cortisol and aldosterone?
Respuesta
The adrenal cortex. It surrounds the adrenal medulla.
Tarjeta 82
Pregunta
Which gland releases melatonin and helps regulate daily sleep timing?
Respuesta
The pineal gland. Light information influences its secretion pattern.
Tarjeta 83
Pregunta
Which hormone directly increases collecting-duct water permeability?
Respuesta
Antidiuretic hormone, or ADH. It makes collecting ducts more permeable to water, increasing water reabsorption and usually producing less, more concentrated urine.
Tarjeta 84
Pregunta
Which hormone strengthens uterine contractions during labor?
Respuesta
Oxytocin. This is a classic positive-feedback pathway that ends after delivery.
Tarjeta 85
Pregunta
How does endocrine signaling generally differ from nervous signaling?
Respuesta
It is usually slower to start and longer lasting. Hormones travel through body fluids, while neurons signal specific targets rapidly.
Tarjeta 86
Pregunta
What is plasma?
Respuesta
The liquid portion of blood. It carries cells, nutrients, hormones, proteins, wastes, and dissolved gases.
Tarjeta 87
Pregunta
Which side of the heart pumps blood to the lungs?
Respuesta
The right side. The right ventricle sends deoxygenated blood through the pulmonary trunk and arteries.
Tarjeta 88
Pregunta
What is the main function of red blood cells?
Respuesta
Transporting oxygen. Their hemoglobin also carries a smaller share of carbon dioxide.
Tarjeta 89
Pregunta
What defines an artery?
Respuesta
It carries blood away from the heart. Oxygen content does not define it; pulmonary arteries carry deoxygenated blood.
Tarjeta 90
Pregunta
What is the main function of white blood cells?
Respuesta
Body defense. Different white blood cells recognize, attack, or coordinate responses to threats.
Tarjeta 91
Pregunta
Which side of the heart pumps blood into systemic circulation?
Respuesta
The left side. The left ventricle sends oxygenated blood into the aorta.
Tarjeta 92
Pregunta
What is the main purpose of heart valves?
Respuesta
To keep blood moving in one direction. Pressure differences open and close them.
Tarjeta 93
Pregunta
What defines a vein?
Respuesta
It carries blood toward the heart. Many veins contain valves that limit backflow.
Tarjeta 94
Pregunta
What is the main role of platelets?
Respuesta
Helping stop bleeding. They form a platelet plug and support clotting reactions at a damaged vessel.
Tarjeta 95
Pregunta
Why are capillaries well suited for exchange?
Respuesta
Their walls are only one cell layer thick. Their small diameter and large total surface area support diffusion and filtration.
Tarjeta 96
Pregunta
After blood enters the right atrium, what chamber receives it next?
Respuesta
The right ventricle. Blood passes through the tricuspid valve before entering that chamber.
Tarjeta 97
Pregunta
What happens during ventricular systole?
Respuesta
The ventricles contract and eject blood. The right ventricle pumps to the lungs, and the left pumps to the body.
Tarjeta 98
Pregunta
What is pulmonary circulation?
Respuesta
Blood flow between the heart and lungs. It allows gas exchange and returns oxygenated blood to the left atrium.
Tarjeta 99
Pregunta
What normally sets the heart's rhythm?
Respuesta
The sinoatrial, or SA, node. Its spontaneous electrical activity initiates each heartbeat.
Tarjeta 100
Pregunta
What molecule in red blood cells binds oxygen?
Respuesta
Hemoglobin. Its iron-containing heme groups bind oxygen reversibly.
Tarjeta 101
Pregunta
What happens during ventricular diastole?
Respuesta
The ventricles relax and fill. Atrioventricular valves are open during most ventricular filling.
Tarjeta 102
Pregunta
What is systemic circulation?
Respuesta
Blood flow between the heart and the body's tissues. It delivers oxygen and nutrients and returns wastes.
Tarjeta 103
Pregunta
What does arterial blood pressure measure?
Respuesta
The force of blood against artery walls. It is commonly reported as systolic over diastolic pressure.
Tarjeta 104
Pregunta
What do coronary arteries supply?
Respuesta
The heart muscle itself. Blocked coronary blood flow can deprive myocardium of oxygen.
Tarjeta 105
Pregunta
Which major vessels return systemic blood to the right atrium?
Respuesta
The superior and inferior venae cavae. The superior vessel drains the upper body; the inferior drains the lower body.
Tarjeta 106
Pregunta
What is the respiratory system's primary gas-exchange function?
Respuesta
Bringing oxygen into the body and removing carbon dioxide. Ventilation moves air, while diffusion exchanges gases.
Tarjeta 107
Pregunta
What is the airflow sequence from the pharynx to the gas-exchange surfaces?
Respuesta
Pharynx, larynx, trachea, bronchi, bronchioles, alveoli. Each branch conducts air deeper into the lungs.
Tarjeta 108
Pregunta
Where does most gas exchange occur in the lungs?
Respuesta
Across the alveolar-capillary membrane. Thin walls and a large surface area shorten diffusion distance.
Tarjeta 109
Pregunta
What does the diaphragm do during quiet inhalation?
Respuesta
It contracts and moves downward. Thoracic volume rises, lung pressure falls, and air flows inward.
Tarjeta 110
Pregunta
Why does oxygen move from alveoli into pulmonary capillaries?
Respuesta
Its partial pressure is higher in alveolar air than in incoming blood. Oxygen diffuses down that gradient.
Tarjeta 111
Pregunta
What drives quiet exhalation?
Respuesta
Elastic recoil after inspiratory muscles relax. Thoracic volume falls and pressure pushes air outward.
Tarjeta 112
Pregunta
What is the pleura?
Respuesta
A double membrane surrounding each lung. A thin fluid layer reduces friction during breathing.
Tarjeta 113
Pregunta
How is most oxygen transported in blood?
Respuesta
Bound to hemoglobin in red blood cells. Only a small amount dissolves directly in plasma.
Tarjeta 114
Pregunta
Why does carbon dioxide move from pulmonary blood into alveoli?
Respuesta
Its partial pressure is higher in incoming blood than in alveolar air. It diffuses down that gradient for exhalation.
Tarjeta 115
Pregunta
What helps keep swallowed material out of the airway?
Respuesta
The epiglottis and coordinated swallowing reflexes. The laryngeal opening is protected as food passes.
Tarjeta 116
Pregunta
How does the conducting airway remove trapped particles?
Respuesta
Mucus traps them, and cilia move the mucus toward the throat. This is the mucociliary escalator.
Tarjeta 117
Pregunta
In what form is most carbon dioxide transported in blood?
Respuesta
As bicarbonate ions. Red blood cells help convert carbon dioxide and water into bicarbonate.
Tarjeta 118
Pregunta
Which blood change is a strong normal stimulus to increase breathing?
Respuesta
A rise in carbon dioxide and the associated fall in pH. Brainstem centers adjust ventilation in response.
Tarjeta 119
Pregunta
Why must alveoli receive both air and blood?
Respuesta
Gas exchange needs ventilation and perfusion. Air without blood flow, or blood without airflow, cannot exchange gases effectively.
Tarjeta 120
Pregunta
Why does ventilation increase during exercise?
Respuesta
Active tissues use more oxygen and produce more carbon dioxide. Faster, deeper breathing helps meet that demand.
Tarjeta 121
Pregunta
What are the digestive system's core functions?
Respuesta
Ingestion, digestion, absorption, and elimination. Movement and secretion support those processes.
Tarjeta 122
Pregunta
What is the alimentary-canal sequence after the mouth?
Respuesta
Pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus. Food passes through this continuous tube.
Tarjeta 123
Pregunta
What is mechanical digestion?
Respuesta
Physical breakdown and mixing of food without changing its molecules. Chewing and stomach churning are examples.
Tarjeta 124
Pregunta
What are two major functions of the stomach?
Respuesta
It stores and mixes food and begins substantial protein digestion. Acid denatures proteins, converts pepsinogen to pepsin, and provides the low pH pepsin needs.
Tarjeta 125
Pregunta
Where does most nutrient absorption occur?
Respuesta
The small intestine. Folds, villi, and microvilli create a large absorptive surface.
Tarjeta 126
Pregunta
Which nutrient does salivary amylase begin digesting in the mouth?
Respuesta
Carbohydrates, especially starch. Salivary amylase breaks starch into smaller carbohydrates.
Tarjeta 127
Pregunta
What is chemical digestion?
Respuesta
Enzymatic breakdown of large food molecules into absorbable units. Chemical bonds are changed during the process.
Tarjeta 128
Pregunta
What is peristalsis?
Respuesta
Wave-like smooth-muscle contractions that move material forward. It occurs throughout much of the digestive tract.
Tarjeta 129
Pregunta
What is a main function of the large intestine?
Respuesta
Absorbing water and electrolytes and forming feces. Resident microbes also process some undigested material.
Tarjeta 130
Pregunta
What digestive product does the liver make?
Respuesta
Bile. Bile salts help disperse dietary fat into smaller droplets.
Tarjeta 131
Pregunta
What does a digestive sphincter do?
Respuesta
It regulates movement between regions of the digestive tract. Circular muscle contracts to close a passage.
Tarjeta 132
Pregunta
What does the pancreas release into the small intestine?
Respuesta
Digestive enzymes and bicarbonate-rich fluid. Bicarbonate helps neutralize acidic material from the stomach.
Tarjeta 133
Pregunta
How do intestinal villi improve absorption?
Respuesta
They increase surface area. Each villus contains blood capillaries and a lymphatic lacteal for transported nutrients.
Tarjeta 134
Pregunta
What is the gallbladder's role?
Respuesta
It stores and concentrates bile. It releases bile into the small intestine when fatty food arrives.
Tarjeta 135
Pregunta
Which macronutrient's absorbed products usually enter intestinal lacteals before reaching the blood?
Respuesta
Most dietary lipids. Their absorbed products travel through lymph before entering the bloodstream.
Tarjeta 136
Pregunta
Which accessory organs help digestion without food passing through them?
Respuesta
The teeth, tongue, salivary glands, liver, gallbladder, and pancreas. Teeth and the tongue act mechanically; the other accessory organs add or store digestive secretions.
Tarjeta 137
Pregunta
What organs make up the urinary system?
Respuesta
The kidneys, ureters, urinary bladder, and urethra. Kidneys make urine; the remaining organs transport, store, and release it.
Tarjeta 138
Pregunta
What is a nephron?
Respuesta
The kidney's functional unit. It filters blood and adjusts the filtrate to form urine.
Tarjeta 139
Pregunta
Where does blood filtration begin in a nephron?
Respuesta
At the renal corpuscle. Pressure pushes water and small solutes from glomerular capillaries into the capsule.
Tarjeta 140
Pregunta
What moves urine from a kidney to the bladder?
Respuesta
A ureter. Smooth-muscle contractions propel urine along the tube.
Tarjeta 141
Pregunta
What is the urinary bladder's main role?
Respuesta
Temporary urine storage. Stretch receptors help trigger the urge to urinate as it fills.
Tarjeta 142
Pregunta
Which structure carries urine from the bladder out of the body?
Respuesta
The urethra. It is distinct from the ureters that enter the bladder.
Tarjeta 143
Pregunta
What is tubular reabsorption?
Respuesta
Movement of useful substances from nephron fluid back into blood. Water, glucose, and ions are common examples.
Tarjeta 144
Pregunta
What is the glomerulus?
Respuesta
A capillary tuft that filters blood in the renal corpuscle. Cells and most large proteins normally remain in circulation.
Tarjeta 145
Pregunta
How does more ADH change urine?
Respuesta
It makes urine more concentrated and lowers its volume. More water is reabsorbed from the collecting ducts.
Tarjeta 146
Pregunta
What path does filtrate follow after entering the glomerular capsule?
Respuesta
Proximal convoluted tubule → nephron loop → distal convoluted tubule → collecting duct. The collecting duct receives forming urine from multiple nephrons.
Tarjeta 147
Pregunta
What is tubular secretion?
Respuesta
Movement of selected substances from blood into nephron fluid. It helps eliminate wastes and regulate ions and pH.
Tarjeta 148
Pregunta
Besides removing waste, what does the urinary system regulate?
Respuesta
Water, electrolytes, acid-base balance, and blood volume. Kidney hormones also affect blood pressure and red-cell production.
Tarjeta 149
Pregunta
Why does dehydration usually reduce urine volume?
Respuesta
The body conserves water by increasing renal reabsorption. ADH is an important signal in this response.
Tarjeta 150
Pregunta
Why do the kidneys receive a large blood flow?
Respuesta
They must continuously filter plasma and regulate its composition. High flow supports waste removal and homeostasis.
Tarjeta 151
Pregunta
What is lymph?
Respuesta
Interstitial fluid that has entered lymphatic vessels. It eventually returns to the bloodstream.
Tarjeta 152
Pregunta
What is innate immunity?
Respuesta
Rapid, nonspecific defense present before a particular exposure. Barriers, inflammation, and several immune cells contribute.
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What is a major function of lymph nodes?
Respuesta
Filtering lymph and providing sites for immune-cell activation. Swelling can reflect an active immune response.
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What does the spleen filter?
Respuesta
Blood. It removes aged blood cells and supports immune responses to blood-borne antigens.
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What is a key function of B lymphocytes?
Respuesta
Producing antibody-secreting cells and memory cells. Antibodies bind specific antigens.
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What distinguishes adaptive immunity?
Respuesta
It targets specific antigens and develops memory. Later exposure can trigger a faster, stronger response.
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Which lymphatic organ is important for T-cell maturation?
Respuesta
The thymus. It is most active early in life.
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What is the body's first physical barrier against many pathogens?
Respuesta
Intact skin and mucous membranes. Their secretions and normal microbes add protection.
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What is a key function of T lymphocytes?
Respuesta
Coordinating immune responses or killing infected cells. Different T-cell types perform different roles.
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What does an antibody bind?
Respuesta
A specific antigen. Binding can neutralize a target or mark it for other immune defenses.
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What is the purpose of inflammation after tissue injury?
Respuesta
To contain damage, recruit defenses, and begin repair. Redness, heat, swelling, and pain can accompany it.
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Why is a second adaptive response often faster than the first?
Respuesta
Memory lymphocytes remain after the first exposure. They respond quickly when the same antigen appears again.
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What does a phagocyte do?
Respuesta
It engulfs particles, microbes, or debris. Neutrophils and macrophages are important examples.
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How does vaccination support adaptive immunity?
Respuesta
It safely exposes the immune system to antigen information. This promotes memory without requiring the full disease.
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Why is lymphatic fluid return important?
Respuesta
It prevents excess interstitial fluid from accumulating. Lymphatic vessels return fluid and leaked proteins to blood.
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What structures belong to the integumentary system?
Respuesta
Skin, hair, nails, sweat glands, and sebaceous glands. Together they form the body's outer covering.
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What is the epidermis?
Respuesta
The outer epithelial layer of skin. It is avascular and contains protective keratinized cells.
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How does sweating cool the body?
Respuesta
Evaporation removes heat from the skin. Skin blood-flow changes also help regulate heat loss.
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What is a major role of melanin in skin?
Respuesta
Absorbing some ultraviolet radiation. It also contributes to skin and hair color.
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How does skin contribute to sensation?
Respuesta
Sensory receptors detect touch, pressure, pain, and temperature. Nerves carry that information to the CNS.
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What is the dermis?
Respuesta
The connective-tissue layer beneath the epidermis. It contains vessels, nerves, glands, and hair follicles.
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How does skin support vitamin D production?
Respuesta
Ultraviolet light starts conversion of a skin molecule into a vitamin D precursor. The liver and kidneys complete activation.
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Why does a deep skin wound bleed but a shallow epidermal scrape may not?
Respuesta
Blood vessels are in the dermis, not the epidermis. A wound must reach vascular tissue to damage them.
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What is a gamete?
Respuesta
A haploid reproductive cell. Human sperm and oocytes each carry 23 chromosomes.
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What are the testes' two main reproductive functions?
Respuesta
Producing sperm and secreting testosterone. Sperm develop in seminiferous tubules.
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What tube carries sperm from the epididymis toward the ejaculatory duct?
Respuesta
The ductus, or vas, deferens. Smooth muscle propels sperm during ejaculation.
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What is ovulation?
Respuesta
Release of a secondary oocyte from an ovary. A surge in luteinizing hormone helps trigger it.
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Where does fertilization usually occur?
Respuesta
In a uterine tube. The early embryo then travels toward the uterus.
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What are the ovaries' two main reproductive functions?
Respuesta
Producing oocytes and secreting sex hormones. Estrogen and progesterone help regulate the reproductive cycle.
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What is the uterus' main reproductive role?
Respuesta
Supporting implantation and development of an embryo and fetus. Its muscular wall also contracts during birth.
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What causes menstruation when pregnancy does not occur?
Respuesta
Falling ovarian hormones allow the uterine lining to shed. A new cycle then begins.
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How does a sperm cell's structure support its function?
Respuesta
Its flagellum provides movement, and its head carries DNA plus enzymes used during fertilization. Mitochondria supply energy in the midpiece.
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What is the placenta's exchange role?
Respuesta
It allows gases, nutrients, and wastes to move between maternal and fetal circulations. Their blood normally does not mix directly.
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Why is meiosis necessary for sexual reproduction?
Respuesta
It halves chromosome number in gametes. Fertilization then restores the diploid number.
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How do sex hormones regulate reproductive control pathways?
Respuesta
They usually feed back on the hypothalamus and pituitary. This adjusts release of hormones that act on the gonads.
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What does cell theory state?
Respuesta
Living things are made of cells, cells are the basic units of life, and cells come from existing cells. These ideas link organism structure with cell division.
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What is the defining structural feature of a prokaryotic cell?
Respuesta
It lacks a membrane-bound nucleus. Its DNA occupies a nucleoid region.
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What is the cell membrane's main role?
Respuesta
Regulating movement between the cell and its environment. Its phospholipid bilayer is selectively permeable.
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What is the nucleus' main role?
Respuesta
Storing most of a eukaryotic cell's DNA. Nuclear pores regulate exchange with the cytoplasm.
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Where are proteins assembled?
Respuesta
At ribosomes. Ribosomes may float in cytosol or attach to rough endoplasmic reticulum.
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What distinguishes a eukaryotic cell from a prokaryotic cell?
Respuesta
A eukaryotic cell has a membrane-bound nucleus and other membrane-bound organelles. Animals, plants, fungi, and protists are eukaryotes.
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What is a mitochondrion's main function?
Respuesta
Producing most cellular ATP through aerobic respiration. Its inner membrane provides a large reaction surface.
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What does rough endoplasmic reticulum mainly produce?
Respuesta
Proteins for secretion, membranes, or organelles. Ribosomes on its surface make the proteins.
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Which organelle carries out photosynthesis in plants and algae?
Respuesta
The chloroplast. It converts light energy into chemical energy stored in organic molecules.
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What does the Golgi apparatus do?
Respuesta
It modifies, sorts, and packages cell products. Vesicles carry those products to their destinations.
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What is a lysosome's role?
Respuesta
Digesting worn cell parts and engulfed material. Its enzymes work best in an acidic interior.
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What are major functions of smooth endoplasmic reticulum?
Respuesta
Lipid synthesis, detoxification, and calcium storage. Its membrane lacks attached ribosomes.
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What does the cytoskeleton provide?
Respuesta
Cell shape, internal organization, movement, and transport tracks. It is built from protein filaments.
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What is diffusion?
Respuesta
Net movement from higher to lower concentration. It is passive and continues until dynamic equilibrium is reached.
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Pregunta
What happens to an animal cell in a strongly hypotonic solution?
Respuesta
Water enters and the cell swells. Without a cell wall, it may burst.
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What happens during interphase?
Respuesta
The cell grows, performs normal functions, and copies its DNA. Interphase precedes mitotic division.
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Pregunta
What is the result of mitosis followed by cytokinesis?
Respuesta
Two genetically similar daughter cells. Chromosome number is normally preserved.
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What is osmosis?
Respuesta
Diffusion of water across a selectively permeable membrane. Water moves toward the side with more nonpenetrating solute.
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What happens to an animal cell in a hypertonic solution?
Respuesta
Water leaves and the cell shrinks. The external solution has a higher effective solute concentration.
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Why are cells generally small?
Respuesta
A high surface-area-to-volume ratio supports efficient exchange. Volume grows faster than surface area as a cell enlarges.
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What is cytokinesis?
Respuesta
Division of the cytoplasm. It separates one cell into two after nuclear division.
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How does active transport differ from passive transport?
Respuesta
It uses energy to move substances against a gradient. Passive transport moves down a gradient without direct energy input.
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What happens to an animal cell in an isotonic solution?
Respuesta
There is no net water movement. Water still crosses in both directions at equal rates.
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Which structures are typical of plant cells but not animal cells?
Respuesta
A cellulose cell wall, chloroplasts, and a large central vacuole. Both cell types have membranes, nuclei, and mitochondria.
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How do cells contribute to a multicellular organism's organization?
Respuesta
Specialized cells form tissues, tissues form organs, and organs form systems. Division of labor supports complex functions.
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What is DNA's primary biological role?
Respuesta
Storing hereditary information. Its nucleotide sequence contains instructions used to build functional RNA and proteins.
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What are the three parts of a DNA nucleotide?
Respuesta
A deoxyribose sugar, a phosphate group, and a nitrogenous base. Nucleotides link to form each strand.
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Which bases pair in double-stranded DNA?
Respuesta
Adenine with thymine, and cytosine with guanine. Hydrogen bonds hold complementary strands together.
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How does RNA differ from DNA?
Respuesta
RNA usually has ribose, uses uracil instead of thymine, and is usually single-stranded. Several RNA types help express genes.
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What is a gene?
Respuesta
A DNA sequence that contributes to a functional product. The product may be a protein or a functional RNA.
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What is a chromosome?
Respuesta
A long DNA molecule packaged with proteins. It contains many genes and other sequences.
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What is DNA replication?
Respuesta
Copying DNA before cell division. Each new DNA molecule contains one old strand and one newly made strand.
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Pregunta
What is the usual flow of information from a protein-coding gene?
Respuesta
DNA to RNA to protein. Transcription makes RNA; translation builds the polypeptide.
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What happens during transcription?
Respuesta
RNA is synthesized from a DNA template. For a protein-coding gene, that RNA functions as or is processed into messenger RNA.
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What does messenger RNA carry?
Respuesta
A copy of coding information from DNA to a ribosome. Its codons specify the amino-acid sequence.
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What is a codon?
Respuesta
A three-nucleotide sequence in mRNA. Most codons specify an amino acid; some signal start or stop.
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Pregunta
What is the usual role of the AUG codon?
Respuesta
It starts translation and specifies methionine. The ribosome uses it to establish the reading frame.
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What happens during translation?
Respuesta
A ribosome reads mRNA and joins amino acids into a polypeptide. Transfer RNAs match codons with amino acids.
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What is transfer RNA's role in protein synthesis?
Respuesta
It carries an amino acid and matches its anticodon to an mRNA codon. This places the correct amino acid in sequence.
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What is an anticodon?
Respuesta
A three-base sequence on tRNA complementary to an mRNA codon. Pairing helps decode the message.
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What is a mutation?
Respuesta
A change in a DNA sequence. Its effect may be harmful, neutral, or beneficial depending on location and context.
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Why can a one-base insertion in a coding sequence have a large effect?
Respuesta
It can shift the reading frame. Every downstream codon may change until a stop signal appears.
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Why can changing one amino acid alter a protein's function?
Respuesta
Amino-acid sequence helps determine folding and shape. Shape controls many protein interactions.
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What is ribosomal RNA's role in protein synthesis?
Respuesta
It forms the structural and catalytic core of ribosomes. Ribosomal RNA helps align translation components and catalyzes peptide-bond formation.
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Why can different cell types contain the same DNA but perform different jobs?
Respuesta
They express different sets of genes. Different proteins give cells different structures and functions.
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Which mutation can be passed to offspring?
Respuesta
A mutation present in a gamete-forming lineage. A mutation limited to ordinary body cells is not inherited through reproduction.
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What is an allele?
Respuesta
An alternative version of a gene. Diploid individuals usually carry two alleles for each autosomal gene.
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What is genotype?
Respuesta
An organism's allele combination for a gene or set of genes. Genotype contributes to phenotype.
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What does homozygous mean?
Respuesta
Having two identical alleles for a gene. Examples include AA and aa.
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Pregunta
What makes an allele dominant in a simple Mendelian trait?
Respuesta
One copy is enough for its phenotype to appear in a heterozygote. Dominant does not mean common or beneficial.
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Pregunta
What does Mendel's law of segregation describe?
Respuesta
The two alleles for a gene separate during gamete formation. Each gamete receives one allele.
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What is phenotype?
Respuesta
An observable trait or characteristic. It can reflect genotype, environment, and their interaction.
Tarjeta 238
Pregunta
What does heterozygous mean?
Respuesta
Having two different alleles for a gene. An example is Aa.
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When does a recessive phenotype usually appear in a simple autosomal trait?
Respuesta
When both alleles are recessive. A heterozygote carries the allele without showing that phenotype.
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When does independent assortment apply most clearly?
Respuesta
When genes are on different chromosomes or far apart on the same chromosome. Their allele pairs enter gametes independently.
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What does a Punnett square predict?
Respuesta
Expected offspring genotype probabilities from specified parental gametes. It does not guarantee outcomes in a small family.
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Pregunta
For Aa × Aa, what is the chance of an aa offspring?
Respuesta
One fourth, or 25%. The genotype ratio is expected to be 1 AA : 2 Aa : 1 aa.
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For Aa × Aa with complete dominance, what phenotypic ratio is expected?
Respuesta
Three dominant-phenotype offspring to one recessive-phenotype offspring. This is a probability across many offspring.
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How can a test cross reveal the genotype behind a dominant phenotype?
Respuesta
Cross the individual with a homozygous recessive partner. Recessive offspring show that the unknown parent carried a recessive allele.
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Pregunta
What happens in incomplete dominance?
Respuesta
A heterozygote has an intermediate phenotype. Neither allele fully masks the other.
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How is the probability of two independent genetic events both occurring found?
Respuesta
Multiply their individual probabilities. This is the product rule.
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What does a pedigree show?
Respuesta
How a trait appears across generations of a family. Its pattern can suggest a mode of inheritance.
Tarjeta 248
Pregunta
Why can two parents have offspring ratios that differ from a Punnett-square expectation?
Respuesta
Each fertilization is a chance event. Expected ratios become more apparent with larger numbers of offspring.
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Pregunta
What happens in codominance?
Respuesta
Both alleles are distinctly expressed in a heterozygote. The AB blood type is a common example.
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What are major roles of carbohydrates?
Respuesta
Providing quick energy, storing energy, and forming some structures. Monosaccharides are their basic building blocks.
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What is a monomer?
Respuesta
A small building block that can join with others to form a larger molecule. Glucose, amino acids, and nucleotides are examples in different classes.
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What happens in a dehydration-synthesis reaction?
Respuesta
Monomers join while water is removed. The reaction builds a larger biological molecule.
Tarjeta 253
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What does an enzyme do?
Respuesta
It lowers activation energy and speeds a reaction without being consumed. Its shape helps it bind specific substrates.
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What are major roles of lipids?
Respuesta
Long-term energy storage, membranes, insulation, and signaling. Lipids are mostly nonpolar and do not mix well with water.
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Pregunta
What does it mean for a protein to denature?
Respuesta
Its normal shape is disrupted. Heat, extreme pH, or chemicals can reduce its function.
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What happens during hydrolysis?
Respuesta
Water is used to split a larger molecule into smaller units. Digestion often uses hydrolysis reactions.
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Why do phospholipids form bilayers in water?
Respuesta
Their hydrophilic heads interact with water while hydrophobic tails turn inward. This arrangement forms cell-membrane structure.
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What are proteins built from?
Respuesta
Amino acids linked by peptide bonds. Their folded shapes support enzymes, transport, signaling, structure, and movement.
Tarjeta 259
Pregunta
How do starch and glycogen compare?
Respuesta
Both store glucose; plants use starch and animals use glycogen. Their branching patterns differ.
Tarjeta 260
Pregunta
How do saturated and unsaturated fatty acids differ?
Respuesta
Saturated fatty acids lack carbon-carbon double bonds; unsaturated ones have one or more. Double bonds often introduce bends.
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Pregunta
What immediate energy-carrying molecule powers many cell processes?
Respuesta
ATP. Energy released from nutrients can be transferred into ATP's phosphate bonds.
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What are nucleic acids built from?
Respuesta
Nucleotides. DNA stores hereditary information, while RNA performs several roles in gene expression.
Tarjeta 263
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Which elements are common in all four major biological macromolecule classes?
Respuesta
Carbon, hydrogen, and oxygen. Nitrogen and phosphorus occur prominently in some classes.
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Pregunta
Why is three-dimensional shape important for macromolecules?
Respuesta
Shape determines many interactions and functions. A changed shape can prevent a molecule from binding its target.
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What are triglycerides built from?
Respuesta
One glycerol molecule and three fatty acids. They join through ester bonds to form a common energy-storage lipid.
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What is a pathogen?
Respuesta
An agent capable of causing disease. Not every microorganism is pathogenic.
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What type of cell is a bacterium?
Respuesta
A prokaryotic cell. Bacteria usually reproduce by binary fission.
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What cell type do fungi have?
Respuesta
Eukaryotic cells. Some fungi are unicellular yeasts, while others form multicellular filaments.
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What does disease transmission describe?
Respuesta
How an infectious agent moves to a susceptible host. Routes include contact, droplets, airborne spread, food, water, and vectors.
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What is a biological vector?
Respuesta
An organism that becomes infected with a pathogen and transmits it between hosts. The pathogen survives or reproduces inside the vector, unlike transport by a mechanical carrier.
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Why are viruses dependent on host cells?
Respuesta
They lack the complete machinery for reproduction and metabolism. They use host components to make new virus particles.
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What is a protist?
Respuesta
A diverse eukaryote that is not classified as an animal, plant, or fungus. Some protists cause disease, while many do not.
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Why do antibiotics not treat viral infections?
Respuesta
They target bacterial structures or processes that viruses lack. Antiviral drugs use different targets.
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How can normal microbiota protect a host?
Respuesta
They occupy space and use resources that pathogens might otherwise exploit. Some also support digestion or immune development.
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How does sterilization differ from disinfection?
Respuesta
Sterilization destroys or removes all microbial life, including resistant forms; disinfection reduces pathogens on objects. The required method depends on use.
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How do infection and disease differ?
Respuesta
Infection means an agent is established in a host; disease means normal function is impaired and signs or symptoms occur. Infection may be asymptomatic.
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How can breaking a transmission route reduce infectious disease?
Respuesta
It interrupts the chain connecting a source with a susceptible host. Hand hygiene, clean water, ventilation, and vector control target different links.
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What is an atom?
Respuesta
The smallest unit of an element that retains that element's chemical identity. Atoms contain a nucleus surrounded by electrons.
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What charge and location does an electron have?
Respuesta
Negative charge in the electron cloud around the nucleus. Electrons drive most chemical bonding.
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Why are valence electrons important?
Respuesta
They participate most directly in bonding and reactions. Their arrangement helps predict chemical behavior.
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What do elements in the same periodic-table group often share?
Respuesta
Similar valence-electron patterns and chemical properties. A group is a vertical column.
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What is an ion?
Respuesta
An atom or group of atoms with a net electric charge. Its total numbers of protons and electrons are unequal.
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What charge and location does a proton have?
Respuesta
Positive charge in the nucleus. The number of protons determines the element.
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What does an element's atomic number equal?
Respuesta
Its number of protons. A neutral atom has the same number of electrons.
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How does a neutral atom form a cation?
Respuesta
By losing one or more electrons. It has more protons than electrons and a positive charge.
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An atom has 8 protons. How many electrons does it have if it is neutral?
Respuesta
Eight electrons. Neutral atoms have equal positive and negative charges.
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What charge and location does a neutron have?
Respuesta
No electric charge, in the nucleus. Neutron number can vary among isotopes of an element.
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What does mass number equal?
Respuesta
Protons plus neutrons in one atom. It is a whole number for a specific isotope.
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How does a neutral atom form an anion?
Respuesta
By gaining one or more electrons. It has more electrons than protons and a negative charge.
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What does a period represent on the periodic table?
Respuesta
A horizontal row. Moving across a period changes proton number one element at a time.
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What are isotopes?
Respuesta
Atoms of the same element with different numbers of neutrons. They have the same atomic number but different mass numbers.
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What is matter?
Respuesta
Anything that has mass and occupies space. Solids, liquids, gases, and plasma are forms of matter.
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What distinguishes a solid from a liquid or gas?
Respuesta
A solid has a definite shape and volume. Its particles vibrate around relatively fixed positions.
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What is a physical change?
Respuesta
A change in form or state without changing chemical identity. Melting and cutting are examples.
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What is a physical property?
Respuesta
A characteristic observed without changing a substance's identity. Density, color, and melting point are examples.
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How does an element differ from a compound?
Respuesta
An element contains one kind of atom; a compound contains elements chemically combined in fixed proportions. Chemical methods can separate a compound into simpler substances.
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What distinguishes a liquid?
Respuesta
It has a definite volume but takes the shape of its container. Its particles remain close while moving past one another.
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What is a chemical change?
Respuesta
A process that forms one or more substances with new chemical identities. Bond rearrangement occurs.
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What is a chemical property?
Respuesta
A substance's ability to undergo a particular chemical change. Flammability and reactivity with acid are examples.
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Which phase changes connect solids and liquids?
Respuesta
Melting changes a solid to a liquid; freezing changes a liquid to a solid. These are opposite physical changes.
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How does a pure substance differ from a mixture?
Respuesta
A pure substance has a fixed composition and is an element or compound; a mixture has variable composition and physically combined components. Mixture components retain their identities.
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What distinguishes a gas?
Respuesta
It has neither a definite shape nor a definite volume. It expands to fill its container.
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Pregunta
What is the formula for density?
Respuesta
Density = mass ÷ volume. Density is an intensive property.
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Pregunta
Which phase changes connect liquids and gases?
Respuesta
Vaporization changes a liquid to a gas; condensation changes a gas to a liquid. Evaporation is vaporization at a liquid's surface.
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Pregunta
What is a mixture?
Respuesta
Two or more substances physically combined in variable proportions. Its components retain their chemical identities.
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Pregunta
How do intensive and extensive properties differ?
Respuesta
Intensive properties do not depend on sample amount; extensive properties do. Density and temperature are intensive, while mass and volume are extensive.
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Pregunta
A 20 g sample occupies 5 mL. What is its density?
Respuesta
4 g/mL. Divide 20 g by 5 mL.
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Pregunta
Which phase changes connect solids and gases directly?
Respuesta
Sublimation changes a solid to a gas; deposition changes a gas to a solid. Neither transition passes through the liquid state.
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Pregunta
How do homogeneous and heterogeneous mixtures differ?
Respuesta
A homogeneous mixture is uniform throughout; a heterogeneous mixture is not. A solution is homogeneous.
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Pregunta
Where are reactants and products written in a chemical equation?
Respuesta
Reactants are on the left; products are on the right. The arrow shows the direction represented.
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Pregunta
Why must a chemical equation be balanced?
Respuesta
Atoms are conserved in ordinary chemical reactions. Each element must have the same atom count on both sides.
Tarjeta 312
Pregunta
What does a coefficient in a chemical equation change?
Respuesta
The number of whole particles or moles represented. It multiplies every atom in the following formula.
Tarjeta 313
Pregunta
Why should subscripts not be changed when balancing an equation?
Respuesta
Changing a subscript changes the substance's identity. Balancing changes coefficients only.
Tarjeta 314
Pregunta
What coefficients balance H₂ + O₂ → H₂O?
Respuesta
2, 1, 2: 2H₂ + O₂ → 2H₂O. Both sides then contain four hydrogen atoms and two oxygen atoms.
Tarjeta 315
Pregunta
What pattern defines a synthesis reaction?
Respuesta
Two or more reactants form a more complex product. A general pattern is A + B → AB.
Tarjeta 316
Pregunta
What are typical products when a hydrocarbon burns completely in oxygen?
Respuesta
Carbon dioxide and water. Incomplete combustion can produce carbon monoxide or carbon.
Tarjeta 317
Pregunta
What is the net ionic equation for a typical strong acid–strong base neutralization?
Respuesta
H⁺(aq) + OH⁻(aq) → H₂O(l). The remaining ions are spectators and do not appear in the net ionic equation.
Tarjeta 318
Pregunta
What is a precipitate?
Respuesta
An insoluble solid that forms from substances in solution. Its appearance can signal a chemical reaction.
Tarjeta 319
Pregunta
What pattern defines a decomposition reaction?
Respuesta
One compound breaks into simpler products. A general pattern is AB → A + B.
Tarjeta 320
Pregunta
What is an exothermic reaction?
Respuesta
A reaction that releases heat to the surroundings. The surroundings often warm.
Tarjeta 321
Pregunta
What occurs in an oxidation-reduction reaction?
Respuesta
Electrons transfer or atoms change oxidation state. Oxidation is electron loss; reduction is electron gain.
Tarjeta 322
Pregunta
What is activation energy?
Respuesta
The minimum energy barrier reactants must overcome to react. Catalysts lower this barrier.
Tarjeta 323
Pregunta
Which observations can provide evidence of a chemical reaction?
Respuesta
Gas formation, a precipitate, sustained color change, light, or temperature change. No single sign proves a reaction without context.
Tarjeta 324
Pregunta
What is an endothermic reaction?
Respuesta
A reaction that absorbs heat from the surroundings. The surroundings may cool.
Tarjeta 325
Pregunta
Why does raising temperature usually speed a reaction?
Respuesta
Particles collide more often and with greater energy. More collisions overcome activation energy.
Tarjeta 326
Pregunta
Why can higher reactant concentration increase reaction rate?
Respuesta
More reactant particles occupy a given volume. This raises collision frequency.
Tarjeta 327
Pregunta
Why does powdered solid often react faster than one large piece?
Respuesta
Powder exposes more surface area. More particles are available for collisions.
Tarjeta 328
Pregunta
How does a catalyst speed a reaction?
Respuesta
It provides a pathway with lower activation energy. The catalyst is regenerated rather than consumed overall.
Tarjeta 329
Pregunta
How can increasing pressure affect a reaction between gases?
Respuesta
It can increase rate by bringing gas particles closer together. Collision frequency rises when volume falls.
Tarjeta 330
Pregunta
What does a reaction inhibitor do?
Respuesta
It slows a reaction. It may block a pathway, interfere with a catalyst, or remove reactive intermediates.
Tarjeta 331
Pregunta
Why can very high temperature slow an enzyme-catalyzed reaction?
Respuesta
The enzyme can denature and lose its active shape. Moderate warming helps only within the enzyme's stable range.
Tarjeta 332
Pregunta
What is dynamic equilibrium?
Respuesta
Forward and reverse reactions continue at equal rates. Concentrations remain constant even though particles still react.
Tarjeta 333
Pregunta
Does a catalyst change the final equilibrium amounts?
Respuesta
No. It speeds forward and reverse reactions, so equilibrium is reached sooner without changing its position.
Tarjeta 334
Pregunta
At equilibrium, what usually happens when the concentration of a dissolved or gaseous reactant increases?
Respuesta
The system shifts toward consuming some added reactant. It forms more product until a new equilibrium is reached.
Tarjeta 335
Pregunta
What is a solution?
Respuesta
A homogeneous mixture. Its components are uniformly distributed at the molecular or ionic level.
Tarjeta 336
Pregunta
How do solute and solvent differ?
Respuesta
The solute is dissolved; the solvent is the dissolving medium. The solvent is often present in greater amount.
Tarjeta 337
Pregunta
What does aqueous mean in chemistry?
Respuesta
Dissolved in water. The symbol
(aq)marks an aqueous species in an equation.Tarjeta 338
Pregunta
What does concentration describe?
Respuesta
The amount of solute in a given amount of solution or solvent. Different units express it in different ways.
Tarjeta 339
Pregunta
What is molarity?
Respuesta
Moles of solute per liter of solution. Its unit is mol/L, written M.
Tarjeta 340
Pregunta
What is the molarity of 0.50 mol solute in 2.0 L of solution?
Respuesta
0.25 M. Divide 0.50 mol by 2.0 L.
Tarjeta 341
Pregunta
What stays constant when water is added to dilute a solution without reaction?
Respuesta
The moles of solute. Volume increases and concentration decreases.
Tarjeta 342
Pregunta
Which equation relates concentration and volume before and after a dilution?
Respuesta
M₁V₁ = M₂V₂. It follows from conserving the amount of solute.
Tarjeta 343
Pregunta
What is solubility?
Respuesta
The maximum concentration of a solute that can be achieved in a solution at equilibrium under specified conditions. Temperature and the substances involved matter.
Tarjeta 344
Pregunta
What is a saturated solution?
Respuesta
A solution holding the maximum dissolved solute at those conditions. Extra solute remains undissolved at equilibrium.
Tarjeta 345
Pregunta
What is an electrolyte?
Respuesta
A substance that produces mobile ions in solution and conducts electricity. Soluble ionic compounds are common examples.
Tarjeta 346
Pregunta
What does 'like dissolves like' predict?
Respuesta
Substances with similar polarity tend to mix well. Polar solvents favor polar or ionic solutes; nonpolar solvents favor nonpolar solutes.
Tarjeta 347
Pregunta
Does heating always increase solubility?
Respuesta
No. Many solids become more soluble in water, but gases usually become less soluble as temperature rises.
Tarjeta 348
Pregunta
What is an unsaturated solution?
Respuesta
A solution that can dissolve more solute at the stated conditions. It is below the solubility limit.
Tarjeta 349
Pregunta
What does a Brønsted-Lowry acid donate?
Respuesta
A proton, H⁺. In water, acid behavior increases hydronium-ion concentration.
Tarjeta 350
Pregunta
What does pH describe?
Respuesta
The hydronium-ion concentration on a logarithmic scale. Lower pH means higher hydronium concentration.
Tarjeta 351
Pregunta
At 25 °C, what pH range is acidic?
Respuesta
Below 7. A neutral aqueous solution is pH 7 at this temperature.
Tarjeta 352
Pregunta
How does hydronium concentration change when pH drops by 1 unit?
Respuesta
It increases tenfold. The pH scale is logarithmic.
Tarjeta 353
Pregunta
What does a Brønsted-Lowry base accept?
Respuesta
A proton, H⁺. Many bases in water also increase hydroxide-ion concentration.
Tarjeta 354
Pregunta
At 25 °C, what is the relationship between pH and pOH?
Respuesta
pH + pOH = 14. pOH is the negative base-10 logarithm of hydroxide-ion concentration; this relation applies to aqueous solutions at 25 °C.
Tarjeta 355
Pregunta
At 25 °C, what pH range is basic?
Respuesta
Above 7. Basic solutions have less hydronium and more hydroxide than neutral water.
Tarjeta 356
Pregunta
What are typical products of a strong acid reacting with a strong base?
Respuesta
Water and an ionic salt. Hydrogen ions and hydroxide ions combine to form water.
Tarjeta 357
Pregunta
What does strong mean for an acid or base?
Respuesta
It produces its characteristic ions essentially completely in water. Strong acids ionize; soluble ionic strong bases dissociate. Strength is separate from concentration.
Tarjeta 358
Pregunta
What does a buffer do?
Respuesta
It resists large pH changes when small amounts of acid or base are added. A weak conjugate acid-base pair neutralizes much of the added H₃O⁺ or OH⁻.
Tarjeta 359
Pregunta
How does an acid-base indicator work?
Respuesta
Its color depends on pH. The change occurs over a characteristic pH range.
Tarjeta 360
Pregunta
A solution has pH 9 at 25 °C. What is its pOH?
Respuesta
5. Subtract the pH from 14.
Tarjeta 361
Pregunta
How does a concentrated weak acid differ from a dilute strong acid?
Respuesta
Concentration tells how much acid is present; strength tells how completely it ionizes. A concentrated weak acid contains more partially ionizing acid, while a dilute strong acid contains less acid that ionizes essentially completely. Either can have the lower pH.
Tarjeta 362
Pregunta
What is the SI base unit of length?
Respuesta
The meter (m). Centimeters and millimeters are decimal subdivisions of a meter.
Tarjeta 363
Pregunta
Which tool directly measures mass in a laboratory?
Respuesta
A balance. A spring scale measures force, often reported as weight.
Tarjeta 364
Pregunta
What is the SI base unit of mass?
Respuesta
The kilogram (kg). Laboratory mass is also commonly reported in grams.
Tarjeta 365
Pregunta
A student needs to measure about 35 mL of liquid and can choose a beaker or graduated cylinder. Which should they use?
Respuesta
A graduated cylinder. Read the scale at eye level.
Tarjeta 366
Pregunta
What is the SI base unit of time?
Respuesta
The second (s). Minutes and hours are accepted for many everyday uses.
Tarjeta 367
Pregunta
Where should the volume of a clear water-based liquid be read in a graduated cylinder?
Respuesta
At the bottom of the meniscus. Keep your eye level with the liquid surface.
Tarjeta 368
Pregunta
What is the SI base unit of thermodynamic temperature?
Respuesta
The kelvin (K). Degrees Celsius are widely used for laboratory and body temperatures.
Tarjeta 369
Pregunta
Which tool measures temperature?
Respuesta
A thermometer. Its range and resolution should match the task.
Tarjeta 370
Pregunta
What factor does the metric prefix kilo- represent?
Respuesta
One thousand, or 10³. One kilometer equals 1,000 meters.
Tarjeta 371
Pregunta
A ruler's smallest marking is 1 mm. To what place should a careful analog reading usually be estimated?
Respuesta
One place beyond the smallest marking, when the scale allows it. The final digit is uncertain.
Tarjeta 372
Pregunta
What is measurement accuracy?
Respuesta
Closeness to an accepted or true value. A systematic error can make precise measurements inaccurate.
Tarjeta 373
Pregunta
How do mass and weight differ?
Respuesta
Mass is the amount of matter; weight is gravitational force on that mass. Mass stays constant when gravity changes, but weight does not.
Tarjeta 374
Pregunta
What factor does the metric prefix milli- represent?
Respuesta
One thousandth, or 10⁻³. One milliliter is 0.001 liter.
Tarjeta 375
Pregunta
How can the volume of an irregular solid be measured with water?
Respuesta
Use water displacement. Subtract the initial water volume from the final volume after submerging the object.
Tarjeta 376
Pregunta
What is measurement precision?
Respuesta
Closeness of repeated measurements to one another. Precise results can still be consistently wrong.
Tarjeta 377
Pregunta
What is an instrument's resolution?
Respuesta
The smallest change it can meaningfully display or distinguish. Higher resolution does not automatically guarantee accuracy.
Tarjeta 378
Pregunta
How many centimeters are in 2.5 meters?
Respuesta
2.5 × 10² cm (250 cm). Multiply meters by the exact conversion factor 100 cm/m.
Tarjeta 379
Pregunta
Why must a numerical measurement include a unit?
Respuesta
The unit identifies the quantity's scale. A bare number is ambiguous and cannot be compared reliably.
Tarjeta 380
Pregunta
What is a scientific observation?
Respuesta
Information recorded with senses or instruments. It should be distinguished from an explanation of what was observed.
Tarjeta 381
Pregunta
What makes a hypothesis scientifically useful?
Respuesta
It is testable and falsifiable. Evidence must be able to count against it.
Tarjeta 382
Pregunta
What is a scientific theory?
Respuesta
A broad, well-supported explanation of natural phenomena. It is not a casual guess and can be revised with new evidence.
Tarjeta 383
Pregunta
Which claim is falsifiable: 'No possible observation could count against this treatment's effectiveness' or 'This treatment lowers mean temperature within one hour'?
Respuesta
The claim that the treatment lowers mean temperature within one hour. An observation could count against it, so evidence can test it.
Tarjeta 384
Pregunta
What is an inference?
Respuesta
A logical interpretation based on observations and prior knowledge. It goes beyond the raw measurement.
Tarjeta 385
Pregunta
How does a prediction relate to a hypothesis?
Respuesta
It states an expected result if the hypothesis is correct. Experiments compare observed results with that expectation.
Tarjeta 386
Pregunta
How does a scientific law differ from a scientific theory?
Respuesta
A law describes a consistent pattern; a theory explains how or why patterns occur. One does not mature into the other.
Tarjeta 387
Pregunta
What does reliability mean for a measurement or procedure?
Respuesta
It produces consistent results under the same conditions. Repetition helps assess reliability.
Tarjeta 388
Pregunta
What does a correlation show?
Respuesta
Two variables change together in a patterned way. Correlation alone does not establish that one causes the other.
Tarjeta 389
Pregunta
What is bias in scientific work?
Respuesta
A systematic influence that pushes observations, selection, or interpretation in one direction. Good design tries to prevent or measure it.
Tarjeta 390
Pregunta
What is the purpose of scientific peer review?
Respuesta
Independent experts evaluate methods, reasoning, and reporting before publication. It improves scrutiny but does not guarantee truth.
Tarjeta 391
Pregunta
What does validity ask about a study or measurement?
Respuesta
Whether it measures or tests what it claims to measure or test. Consistency alone does not ensure validity.
Tarjeta 392
Pregunta
What evidence most strengthens a causal claim?
Respuesta
A well-controlled experiment that manipulates the suspected cause. Random assignment reduces confounding, while independent replication tests whether the result holds with new data.
Tarjeta 393
Pregunta
What is a primary scientific source?
Respuesta
A report of original methods, data, and results. A review article synthesizes many primary studies.
Tarjeta 394
Pregunta
How should an unexpected outlier be handled?
Respuesta
Investigate and report it rather than deleting it automatically. Exclusion needs a documented scientific reason.
Tarjeta 395
Pregunta
What is a confounding variable?
Respuesta
An outside factor related to both the suspected cause and the outcome. It can create a misleading association.
Tarjeta 396
Pregunta
Why should a sample represent the population of interest?
Respuesta
Results generalize poorly when important groups are missing or overrepresented. Sampling method matters as much as size.
Tarjeta 397
Pregunta
What is a scientific model?
Respuesta
A simplified representation used to explain or predict a system. A model is useful within its assumptions and limits.
Tarjeta 398
Pregunta
Why should measurements report uncertainty or reasonable precision?
Respuesta
Every measurement has limits. Reporting more digits than the method supports creates false precision.
Tarjeta 399
Pregunta
If results match a prediction once, what is the safest conclusion?
Respuesta
The results support the hypothesis under those conditions. One result does not prove the hypothesis in every setting.
Tarjeta 400
Pregunta
What is a direct relationship between two variables?
Respuesta
As one increases, the other tends to increase; as one decreases, the other tends to decrease. The relationship need not be perfectly linear.
Tarjeta 401
Pregunta
Which variable is usually placed on the x-axis of an experimental graph?
Respuesta
The independent variable. It is the factor selected or changed by the investigator.
Tarjeta 402
Pregunta
What does the slope of a straight-line graph represent?
Respuesta
Change in y divided by change in x. It is the response rate per unit change in the other variable.
Tarjeta 403
Pregunta
A line rises 12 units in y while x rises 3 units. What is its slope?
Respuesta
4 units of y per unit of x. Divide 12 by 3.
Tarjeta 404
Pregunta
What is an inverse relationship?
Respuesta
As one variable increases, the other tends to decrease. Their product is constant only in a strictly inverse proportion.
Tarjeta 405
Pregunta
Which variable is usually placed on the y-axis of an experimental graph?
Respuesta
The dependent variable. It is the measured response.
Tarjeta 406
Pregunta
What does a plateau on a response graph indicate?
Respuesta
The measured response has stopped changing much despite further x increases. A limiting factor may have been reached.
Tarjeta 407
Pregunta
What is interpolation?
Respuesta
Estimating a value within the range of measured data. It is generally safer than extrapolating beyond that range.
Tarjeta 408
Pregunta
What pattern suggests no relationship between two plotted variables?
Respuesta
The response shows no consistent change as the other variable changes. Points may scatter without a trend.
Tarjeta 409
Pregunta
Before comparing values in a data table, what should you check?
Respuesta
Headings, units, and conditions. Numbers from different measures or scales cannot be compared directly.
Tarjeta 410
Pregunta
If 3 samples require 12 mL total, how much is needed for 5 equal samples?
Respuesta
20 mL. The rate is 4 mL per sample, so multiply by 5.
Tarjeta 411
Pregunta
How is the arithmetic mean calculated?
Respuesta
Add all values and divide by the number of values. A large outlier can shift the mean.
Tarjeta 412
Pregunta
Why is extrapolation uncertain?
Respuesta
It assumes the observed trend continues outside measured conditions. The relationship may change beyond the data range.
Tarjeta 413
Pregunta
A culture grows from 20 to 50 cells in 6 hours. What is the average growth rate?
Respuesta
5 cells per hour. The change is 30 cells divided by 6 hours.
Tarjeta 414
Pregunta
A measurement rises from 40 to 50. What is the percent increase?
Respuesta
25%. The increase is 10, and 10 ÷ 40 × 100 = 25%.
Tarjeta 415
Pregunta
When can the median describe a typical value better than the mean?
Respuesta
When data are skewed or contain strong outliers. In an ordered set, the median is the middle value for an odd count and the mean of the two middle values for an even count.
Tarjeta 416
Pregunta
How do quantitative and qualitative data differ?
Respuesta
Quantitative data are numerical; qualitative data describe categories or qualities. Both can answer scientific questions.
Tarjeta 417
Pregunta
A response is 2 at dose 1, 4 at dose 2, and 8 at dose 4. If the relationship is linear, what response is predicted at dose 3?
Respuesta
6. The observed rate is 2 response units per dose unit, so interpolation at dose 3 gives 6.
Tarjeta 418
Pregunta
How can a graph reveal a nonlinear relationship?
Respuesta
The points follow a curve rather than a straight line. The rate of change varies across the x-range.
Tarjeta 419
Pregunta
What is the range of a data set?
Respuesta
Maximum minus minimum. It describes total spread but ignores the distribution between the endpoints.
Tarjeta 420
Pregunta
What makes a scientific research question testable?
Respuesta
It identifies measurable variables or observable outcomes. The needed data must be obtainable.
Tarjeta 421
Pregunta
In an experiment, what is the independent variable?
Respuesta
The factor deliberately changed or assigned by the investigator. In a simple one-factor experiment, changing one independent variable helps isolate its effect.
Tarjeta 422
Pregunta
What should a hypothesis connect?
Respuesta
A proposed explanation with a measurable outcome. It should lead to a prediction that evidence can challenge.
Tarjeta 423
Pregunta
What is a controlled variable, or constant?
Respuesta
A condition kept the same across groups. Holding it constant prevents it from explaining outcome differences.
Tarjeta 424
Pregunta
What is the purpose of a control group?
Respuesta
It provides a comparison without the experimental treatment. Differences can then be attributed more confidently to the treatment.
Tarjeta 425
Pregunta
In an experiment, what is the dependent variable?
Respuesta
The measured response. It may change because of the independent variable.
Tarjeta 426
Pregunta
What form can a useful experimental prediction take?
Respuesta
If the independent variable changes in a stated way, then the dependent variable should respond in a stated way. The reason links it to the hypothesis.
Tarjeta 427
Pregunta
What does a positive control demonstrate?
Respuesta
That the setup can produce a known response. If it fails, the test system may be defective.
Tarjeta 428
Pregunta
Why randomly assign subjects to experimental groups?
Respuesta
To distribute known and unknown differences more evenly. This reduces selection bias and confounding.
Tarjeta 429
Pregunta
How can blinding reduce bias?
Respuesta
It keeps participants, observers, or both unaware of treatment assignments. Expectations are less likely to affect behavior or measurement.
Tarjeta 430
Pregunta
What is a placebo?
Respuesta
An inactive treatment designed to resemble the experimental treatment. It helps separate treatment effects from expectation effects.
Tarjeta 431
Pregunta
What does a negative control demonstrate?
Respuesta
What happens when the tested cause is absent. An unexpected response may reveal contamination or another source.
Tarjeta 432
Pregunta
Why does a larger sample often improve a study?
Respuesta
It reduces the influence of chance variation and supports more stable estimates. It cannot repair a biased sampling method.
Tarjeta 433
Pregunta
Why repeat trials within an experiment?
Respuesta
To estimate variability and check consistency. One unusual trial then has less influence.
Tarjeta 434
Pregunta
Why must an experimental procedure be detailed and standardized?
Respuesta
So groups are treated consistently and others can reproduce the work. Uncontrolled procedural differences create alternative explanations.
Tarjeta 435
Pregunta
Why calibrate a measuring instrument before collecting data?
Respuesta
To compare its readings with a known standard and reduce systematic error. Calibration improves confidence in accuracy.
Tarjeta 436
Pregunta
What is an operational definition?
Respuesta
A precise statement of how a variable is measured or manipulated. It turns an abstract concept into a repeatable procedure.
Tarjeta 437
Pregunta
How does independent replication differ from repeated trials?
Respuesta
Independent replication repeats a study with independently collected data, often by a different investigator; repeated trials rerun measurements within the original experiment. Replication tests consistency across separate studies.
Tarjeta 438
Pregunta
Why should raw data be recorded before interpretation?
Respuesta
It preserves the observations separately from conclusions. Others can check calculations and reasoning.
Tarjeta 439
Pregunta
What should a scientific conclusion do?
Respuesta
Answer the research question using the data and acknowledge limits. It should not claim more than the design supports.
Tarjeta 440
Pregunta
What should happen when data do not support a hypothesis?
Respuesta
Revise or reject the hypothesis and consider new tests. Data should not be altered to preserve the original idea.
Tarjeta 441
Pregunta
What is a study limitation?
Respuesta
A feature that restricts interpretation or generalization. Small samples, short duration, and imperfect measurements are examples.
Tarjeta 442
Pregunta
Why are ethics part of experimental design?
Respuesta
Research must protect participants, organisms, and communities while balancing risks and benefits. Consent and humane treatment are key examples.
Tarjeta 443
Pregunta
How does an observational study differ from an experiment?
Respuesta
It measures variables without assigning the exposure. It can find associations but usually supports weaker causal conclusions.
Tarjeta 444
Pregunta
Plants receive 0, 2, or 4 hours of added light, and growth is measured. What is the independent variable?
Respuesta
Hours of added light. Plant growth is the dependent variable.
Tarjeta 445
Pregunta
A fertilizer study gives every plant the same water, soil, and temperature. What are these conditions?
Respuesta
Controlled variables. Keeping them constant isolates the fertilizer's effect.
Tarjeta 446
Pregunta
A drug group improves more than a control group, but the groups were not randomly assigned. What is the main caution?
Respuesta
Preexisting group differences could explain some improvement. The result is suggestive, but the design weakens a causal claim.
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ATI TEAS 7 Science Flashcards: A&P, Biology, Chemistry & Scientific Reasoning
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