What posture defines the standard anatomical position?

Standing upright, facing forward, with arms at the sides and palms forward. The feet point forward, giving anatomy a consistent reference position.

In anatomical language, what does superior mean?

Toward the head or above another structure. Inferior means toward the feet or below.

Which anatomical plane divides the body into left and right portions?

The sagittal plane. A midsagittal plane divides the body into equal left and right halves.

Why does the body use feedback mechanisms?

To regulate internal conditions. Feedback compares a condition with a set range and triggers responses that adjust it.

What is the order of structural organization from simplest to most complex?

Chemical, cellular, tissue, organ, organ system, organism. Each level builds on interactions at the preceding level.

What does anterior mean in human anatomy?

Toward the front of the body. Posterior means toward the back.

Which plane divides the body into upper and lower portions?

The transverse plane. It is also called the horizontal plane.

The maintenance of a relatively stable internal environment. It is dynamic rather than perfectly unchanging.

Which major body cavity contains the brain and spinal cord?

The dorsal body cavity. Its cranial cavity holds the brain, and its vertebral cavity holds the spinal cord.

What does medial mean in anatomical language?

Toward the body's midline. Lateral means farther from the midline.

A rise in body temperature triggers sweating. What control pattern is this?

Negative feedback. The response opposes the original temperature change and moves the body toward its normal range.

Which anatomical plane divides the body into front and back portions?

The frontal, or coronal, plane. It separates anterior from posterior portions.

Which major body cavity contains the thoracic and abdominopelvic cavities?

The ventral body cavity. The diaphragm separates its thoracic and abdominopelvic portions.

What does proximal mean when describing a limb?

Closer to the limb's point of attachment. Distal means farther from that point.

How does positive feedback differ from negative feedback?

Positive feedback amplifies the initial change. Negative feedback opposes a change; positive feedback continues until a stopping event occurs.

Which tissue type covers surfaces and lines body cavities?

Epithelial tissue. It also forms many glands and often serves protective, absorptive, or secretory roles.

Which tissue type mainly supports, binds, and protects other tissues?

Connective tissue. Its cells are typically separated by an extracellular matrix.

What shared property lets muscle tissue produce movement?

Contractility. Muscle cells shorten or develop tension in response to stimulation.

Which tissue type rapidly communicates by electrical signals?

Nervous tissue. Neurons transmit signals, while supporting cells help maintain their environment.

Why are tightly packed epithelial cells well suited for barriers?

They leave little space between cells. This continuous arrangement limits passage across a surface.

What distinguishes connective tissue from epithelial tissue?

Connective tissue usually has abundant extracellular matrix. Epithelial cells are more tightly packed.

What are the four basic human tissue types?

Epithelial, connective, muscle, and nervous tissue. Organs contain two or more tissue types working together.

What makes a structure an organ rather than a tissue?

An organ combines multiple tissue types for a specific function. A tissue is a group of similar cells and matrix performing related work.

What are the skeletal system's main functions?

Support, protection, movement, mineral storage, blood-cell production, and fat storage. Bones also provide levers for muscles.

What belongs to the axial skeleton?

The skull, vertebral column, and thoracic cage. These structures form the body's central axis.

How do compact and spongy bone differ?

Compact bone is dense; spongy bone has a lattice of trabeculae. Both are organized living bone tissue.

A place where two or more bones meet. Joint structure determines how much movement is possible.

Which bone cell builds new bone matrix?

An osteoblast. Osteoclasts break down bone, while osteocytes maintain mature bone tissue.

What belongs to the appendicular skeleton?

The limbs plus the shoulder and pelvic girdles. It attaches the limbs to the axial skeleton.

What is the main role of red bone marrow?

Blood-cell production. This process is called hematopoiesis.

Which joint class allows the greatest range of motion?

A synovial joint. A fluid-filled joint cavity reduces friction between articulating surfaces.

Which bone cell breaks down bone matrix?

An osteoclast. Bone resorption helps remodeling and mineral balance.

What does a ligament connect?

Bone to bone. A tendon connects muscle to bone.

What is the shaft of a long bone called?

The diaphysis. The enlarged ends are the epiphyses.

Why is bone important to blood-calcium balance?

Bone stores calcium and can release or absorb it during remodeling. Hormones regulate this exchange.

What is stored mainly in yellow bone marrow?

Fat. It serves as an energy reserve.

What does articular cartilage do at a synovial joint?

It reduces friction and absorbs shock. It covers the ends of articulating bones.

Why must a broken bone receive a blood supply during healing?

Repairing cells need oxygen and nutrients. Restored blood vessels support fracture healing.

What is bone remodeling?

Continuous removal and replacement of bone tissue. It repairs microdamage and helps bones adapt to stress.

Which muscle tissue is usually under voluntary control?

Skeletal muscle. Most skeletal muscles move the skeleton, while some, such as facial muscles, insert into skin or other soft tissue.

The basic contractile unit of striated muscle. It lies between two Z discs.

What does a tendon connect?

Muscle to bone. It transmits muscle force to the skeleton.

Which proteins slide past one another during muscle contraction?

Actin and myosin. Their interaction shortens sarcomeres without shortening the filaments themselves.

Where is smooth muscle commonly found?

In the walls of hollow organs and blood vessels. Its contractions are generally involuntary.

What ion exposes binding sites needed for skeletal muscle contraction?

Calcium. Its release inside the muscle fiber allows actin and myosin interaction.

How do antagonistic muscle pairs move a joint?

One muscle contracts while the opposing muscle relaxes. Reversing their roles moves the joint in the opposite direction.

Why does muscle contraction require ATP?

ATP powers cross-bridge cycling and ion pumps. It is also needed for myosin to detach from actin.

Which muscle tissue makes up the heart wall?

Cardiac muscle. It is striated, involuntary, and connected for coordinated pumping.

During a typical muscle contraction, which attachment moves more: origin or insertion?

The insertion. The origin is generally the more fixed attachment.

Which type of neuron sends the signal that initiates skeletal-muscle contraction?

A somatic motor neuron. It releases acetylcholine at the neuromuscular junction, triggering an action potential in the muscle fiber.

Continuous low-level muscle tension. It helps maintain posture and readiness without producing a large movement.

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.

Par Flashcards Open Source App

À propos de ce paquet

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.

Cartes de ce paquet

Carte 1
Question
What posture defines the standard anatomical position?
Réponse
Standing upright, facing forward, with arms at the sides and palms forward. The feet point forward, giving anatomy a consistent reference position.
Carte 2
Question
In anatomical language, what does superior mean?
Réponse
Toward the head or above another structure. Inferior means toward the feet or below.
Carte 3
Question
Which anatomical plane divides the body into left and right portions?
Réponse
The sagittal plane. A midsagittal plane divides the body into equal left and right halves.
Carte 4
Question
Why does the body use feedback mechanisms?
Réponse
To regulate internal conditions. Feedback compares a condition with a set range and triggers responses that adjust it.
Carte 5
Question
What is the order of structural organization from simplest to most complex?
Réponse
Chemical, cellular, tissue, organ, organ system, organism. Each level builds on interactions at the preceding level.
Carte 6
Question
What does anterior mean in human anatomy?
Réponse
Toward the front of the body. Posterior means toward the back.
Carte 7
Question
Which plane divides the body into upper and lower portions?
Réponse
The transverse plane. It is also called the horizontal plane.
Carte 8
Question
What is homeostasis?
Réponse
The maintenance of a relatively stable internal environment. It is dynamic rather than perfectly unchanging.
Carte 9
Question
Which major body cavity contains the brain and spinal cord?
Réponse
The dorsal body cavity. Its cranial cavity holds the brain, and its vertebral cavity holds the spinal cord.
Carte 10
Question
What does medial mean in anatomical language?
Réponse
Toward the body's midline. Lateral means farther from the midline.
Carte 11
Question
A rise in body temperature triggers sweating. What control pattern is this?
Réponse
Negative feedback. The response opposes the original temperature change and moves the body toward its normal range.
Carte 12
Question
Which anatomical plane divides the body into front and back portions?
Réponse
The frontal, or coronal, plane. It separates anterior from posterior portions.
Carte 13
Question
Which major body cavity contains the thoracic and abdominopelvic cavities?
Réponse
The ventral body cavity. The diaphragm separates its thoracic and abdominopelvic portions.
Carte 14
Question
What does proximal mean when describing a limb?
Réponse
Closer to the limb's point of attachment. Distal means farther from that point.
Carte 15
Question
How does positive feedback differ from negative feedback?
Réponse
Positive feedback amplifies the initial change. Negative feedback opposes a change; positive feedback continues until a stopping event occurs.
Carte 16
Question
Which tissue type covers surfaces and lines body cavities?
Réponse
Epithelial tissue. It also forms many glands and often serves protective, absorptive, or secretory roles.
Carte 17
Question
Which tissue type mainly supports, binds, and protects other tissues?
Réponse
Connective tissue. Its cells are typically separated by an extracellular matrix.
Carte 18
Question
What shared property lets muscle tissue produce movement?
Réponse
Contractility. Muscle cells shorten or develop tension in response to stimulation.
Carte 19
Question
Which tissue type rapidly communicates by electrical signals?
Réponse
Nervous tissue. Neurons transmit signals, while supporting cells help maintain their environment.
Carte 20
Question
Why are tightly packed epithelial cells well suited for barriers?
Réponse
They leave little space between cells. This continuous arrangement limits passage across a surface.
Carte 21
Question
What distinguishes connective tissue from epithelial tissue?
Réponse
Connective tissue usually has abundant extracellular matrix. Epithelial cells are more tightly packed.
Carte 22
Question
What are the four basic human tissue types?
Réponse
Epithelial, connective, muscle, and nervous tissue. Organs contain two or more tissue types working together.
Carte 23
Question
What makes a structure an organ rather than a tissue?
Réponse
An organ combines multiple tissue types for a specific function. A tissue is a group of similar cells and matrix performing related work.
Carte 24
Question
What are the skeletal system's main functions?
Réponse
Support, protection, movement, mineral storage, blood-cell production, and fat storage. Bones also provide levers for muscles.
Carte 25
Question
What belongs to the axial skeleton?
Réponse
The skull, vertebral column, and thoracic cage. These structures form the body's central axis.
Carte 26
Question
How do compact and spongy bone differ?
Réponse
Compact bone is dense; spongy bone has a lattice of trabeculae. Both are organized living bone tissue.
Carte 27
Question
What is a joint?
Réponse
A place where two or more bones meet. Joint structure determines how much movement is possible.
Carte 28
Question
Which bone cell builds new bone matrix?
Réponse
An osteoblast. Osteoclasts break down bone, while osteocytes maintain mature bone tissue.
Carte 29
Question
What belongs to the appendicular skeleton?
Réponse
The limbs plus the shoulder and pelvic girdles. It attaches the limbs to the axial skeleton.
Carte 30
Question
What is the main role of red bone marrow?
Réponse
Blood-cell production. This process is called hematopoiesis.
Carte 31
Question
Which joint class allows the greatest range of motion?
Réponse
A synovial joint. A fluid-filled joint cavity reduces friction between articulating surfaces.
Carte 32
Question
Which bone cell breaks down bone matrix?
Réponse
An osteoclast. Bone resorption helps remodeling and mineral balance.
Carte 33
Question
What does a ligament connect?
Réponse
Bone to bone. A tendon connects muscle to bone.
Carte 34
Question
What is the shaft of a long bone called?
Réponse
The diaphysis. The enlarged ends are the epiphyses.
Carte 35
Question
Why is bone important to blood-calcium balance?
Réponse
Bone stores calcium and can release or absorb it during remodeling. Hormones regulate this exchange.
Carte 36
Question
What is stored mainly in yellow bone marrow?
Réponse
Fat. It serves as an energy reserve.
Carte 37
Question
What does articular cartilage do at a synovial joint?
Réponse
It reduces friction and absorbs shock. It covers the ends of articulating bones.
Carte 38
Question
Why must a broken bone receive a blood supply during healing?
Réponse
Repairing cells need oxygen and nutrients. Restored blood vessels support fracture healing.
Carte 39
Question
What is bone remodeling?
Réponse
Continuous removal and replacement of bone tissue. It repairs microdamage and helps bones adapt to stress.
Carte 40
Question
Which muscle tissue is usually under voluntary control?
Réponse
Skeletal muscle. Most skeletal muscles move the skeleton, while some, such as facial muscles, insert into skin or other soft tissue.
Carte 41
Question
What is a sarcomere?
Réponse
The basic contractile unit of striated muscle. It lies between two Z discs.
Carte 42
Question
What does a tendon connect?
Réponse
Muscle to bone. It transmits muscle force to the skeleton.
Carte 43
Question
Which proteins slide past one another during muscle contraction?
Réponse
Actin and myosin. Their interaction shortens sarcomeres without shortening the filaments themselves.
Carte 44
Question
Where is smooth muscle commonly found?
Réponse
In the walls of hollow organs and blood vessels. Its contractions are generally involuntary.
Carte 45
Question
What ion exposes binding sites needed for skeletal muscle contraction?
Réponse
Calcium. Its release inside the muscle fiber allows actin and myosin interaction.
Carte 46
Question
How do antagonistic muscle pairs move a joint?
Réponse
One muscle contracts while the opposing muscle relaxes. Reversing their roles moves the joint in the opposite direction.
Carte 47
Question
Why does muscle contraction require ATP?
Réponse
ATP powers cross-bridge cycling and ion pumps. It is also needed for myosin to detach from actin.
Carte 48
Question
Which muscle tissue makes up the heart wall?
Réponse
Cardiac muscle. It is striated, involuntary, and connected for coordinated pumping.
Carte 49
Question
During a typical muscle contraction, which attachment moves more: origin or insertion?
Réponse
The insertion. The origin is generally the more fixed attachment.
Carte 50
Question
Which type of neuron sends the signal that initiates skeletal-muscle contraction?
Réponse
A somatic motor neuron. It releases acetylcholine at the neuromuscular junction, triggering an action potential in the muscle fiber.
Carte 51
Question
What is muscle tone?
Réponse
Continuous low-level muscle tension. It helps maintain posture and readiness without producing a large movement.
Carte 52
Question
How does skeletal muscle help regulate body temperature?
Réponse
Contraction releases heat. Shivering increases rapid contractions when the body is cold.
Carte 53
Question
What are the three muscle tissue types?
Réponse
Skeletal, cardiac, and smooth muscle. They differ in location, structure, and control.
Carte 54
Question
What is a neuron's main function?
Réponse
To receive, process, and transmit information. Neurons use electrical signals and chemical messengers.
Carte 55
Question
What structures make up the central nervous system?
Réponse
The brain and spinal cord. They integrate information and coordinate responses.
Carte 56
Question
Which part of a neuron usually receives incoming signals?
Réponse
The dendrites. The cell body integrates much of that input.
Carte 57
Question
What does the peripheral nervous system include?
Réponse
Nerves and ganglia outside the brain and spinal cord. It links the central nervous system with the rest of the body.
Carte 58
Question
Which neuron structure carries an impulse away from the cell body?
Réponse
The axon. Its terminals communicate with another cell.
Carte 59
Question
Which nervous-system division controls skeletal muscles voluntarily?
Réponse
The somatic nervous system. It also carries sensory information from skin, muscles, and joints.
Carte 60
Question
What is a synapse?
Réponse
A junction where one neuron communicates with another cell. Chemical synapses use neurotransmitters across a small gap.
Carte 61
Question
Which nervous-system division regulates organs and glands without conscious control?
Réponse
The autonomic nervous system. It includes sympathetic and parasympathetic divisions.
Carte 62
Question
How does myelin affect nerve signaling?
Réponse
It speeds impulse conduction along an axon. Myelin insulates segments of the axon.
Carte 63
Question
Which autonomic division prepares the body for acute activity?
Réponse
The sympathetic division. It generally increases alertness and supports a fight-or-flight response.
Carte 64
Question
What is a reflex?
Réponse
A rapid, predictable response to a stimulus. A reflex pathway can act before conscious awareness.
Carte 65
Question
Which autonomic division supports rest, digestion, and energy conservation?
Réponse
The parasympathetic division. It generally promotes routine maintenance functions.
Carte 66
Question
Which brain region is most associated with conscious thought and voluntary movement?
Réponse
The cerebrum. Its cortex also processes much sensory information.
Carte 67
Question
Which brain region fine-tunes balance and coordinated movement?
Réponse
The cerebellum. It compares intended movement with sensory feedback.
Carte 68
Question
Which brain region controls vital automatic functions such as breathing and heart rate?
Réponse
The brainstem. It also connects higher brain regions with the spinal cord.
Carte 69
Question
How do sensory and motor neurons differ?
Réponse
Sensory neurons carry information toward the CNS; motor neurons carry commands away. Interneurons connect and process signals within the CNS.
Carte 70
Question
What does a sensory receptor do?
Réponse
It converts a stimulus into a neural signal. Different receptors respond best to particular forms of energy or chemicals.
Carte 71
Question
What is a hormone?
Réponse
A chemical messenger released into body fluids to affect target cells. A target responds only if it has the appropriate receptor.
Carte 72
Question
Why is the pituitary gland often called a master gland?
Réponse
Several pituitary hormones regulate other endocrine glands. The hypothalamus controls much of pituitary activity.
Carte 73
Question
Why can one hormone affect some cells but not others?
Réponse
Only target cells have the matching receptor. Receptor binding starts the cell's response.
Carte 74
Question
Which gland produces hormones that broadly increase metabolic activity?
Réponse
The thyroid gland. Thyroid hormones influence energy use and development.
Carte 75
Question
What is insulin's main effect on blood glucose?
Réponse
It lowers blood glucose. Insulin promotes glucose uptake and storage after a meal.
Carte 76
Question
Which glands release a hormone that raises blood calcium?
Réponse
The parathyroid glands. Parathyroid hormone acts on bone, kidneys, and vitamin D pathways.
Carte 77
Question
Which adrenal region releases epinephrine during acute stress?
Réponse
The adrenal medulla. Its hormones reinforce sympathetic nervous-system effects.
Carte 78
Question
Which organ has both endocrine and digestive functions?
Réponse
The pancreas. Its islets release hormones, while other cells release digestive enzymes.
Carte 79
Question
What is glucagon's main effect on blood glucose?
Réponse
It raises blood glucose. It promotes release of stored glucose during fasting.
Carte 80
Question
Rising thyroid hormone reduces its own upstream stimulation. What pattern is this?
Réponse
Negative feedback. The final hormone limits further release along the control pathway.
Carte 81
Question
Which adrenal region produces steroid hormones such as cortisol and aldosterone?
Réponse
The adrenal cortex. It surrounds the adrenal medulla.
Carte 82
Question
Which gland releases melatonin and helps regulate daily sleep timing?
Réponse
The pineal gland. Light information influences its secretion pattern.
Carte 83
Question
Which hormone directly increases collecting-duct water permeability?
Réponse
Antidiuretic hormone, or ADH. It makes collecting ducts more permeable to water, increasing water reabsorption and usually producing less, more concentrated urine.
Carte 84
Question
Which hormone strengthens uterine contractions during labor?
Réponse
Oxytocin. This is a classic positive-feedback pathway that ends after delivery.
Carte 85
Question
How does endocrine signaling generally differ from nervous signaling?
Réponse
It is usually slower to start and longer lasting. Hormones travel through body fluids, while neurons signal specific targets rapidly.
Carte 86
Question
What is plasma?
Réponse
The liquid portion of blood. It carries cells, nutrients, hormones, proteins, wastes, and dissolved gases.
Carte 87
Question
Which side of the heart pumps blood to the lungs?
Réponse
The right side. The right ventricle sends deoxygenated blood through the pulmonary trunk and arteries.
Carte 88
Question
What is the main function of red blood cells?
Réponse
Transporting oxygen. Their hemoglobin also carries a smaller share of carbon dioxide.
Carte 89
Question
What defines an artery?
Réponse
It carries blood away from the heart. Oxygen content does not define it; pulmonary arteries carry deoxygenated blood.
Carte 90
Question
What is the main function of white blood cells?
Réponse
Body defense. Different white blood cells recognize, attack, or coordinate responses to threats.
Carte 91
Question
Which side of the heart pumps blood into systemic circulation?
Réponse
The left side. The left ventricle sends oxygenated blood into the aorta.
Carte 92
Question
What is the main purpose of heart valves?
Réponse
To keep blood moving in one direction. Pressure differences open and close them.
Carte 93
Question
What defines a vein?
Réponse
It carries blood toward the heart. Many veins contain valves that limit backflow.
Carte 94
Question
What is the main role of platelets?
Réponse
Helping stop bleeding. They form a platelet plug and support clotting reactions at a damaged vessel.
Carte 95
Question
Why are capillaries well suited for exchange?
Réponse
Their walls are only one cell layer thick. Their small diameter and large total surface area support diffusion and filtration.
Carte 96
Question
After blood enters the right atrium, what chamber receives it next?
Réponse
The right ventricle. Blood passes through the tricuspid valve before entering that chamber.
Carte 97
Question
What happens during ventricular systole?
Réponse
The ventricles contract and eject blood. The right ventricle pumps to the lungs, and the left pumps to the body.
Carte 98
Question
What is pulmonary circulation?
Réponse
Blood flow between the heart and lungs. It allows gas exchange and returns oxygenated blood to the left atrium.
Carte 99
Question
What normally sets the heart's rhythm?
Réponse
The sinoatrial, or SA, node. Its spontaneous electrical activity initiates each heartbeat.
Carte 100
Question
What molecule in red blood cells binds oxygen?
Réponse
Hemoglobin. Its iron-containing heme groups bind oxygen reversibly.
Carte 101
Question
What happens during ventricular diastole?
Réponse
The ventricles relax and fill. Atrioventricular valves are open during most ventricular filling.
Carte 102
Question
What is systemic circulation?
Réponse
Blood flow between the heart and the body's tissues. It delivers oxygen and nutrients and returns wastes.
Carte 103
Question
What does arterial blood pressure measure?
Réponse
The force of blood against artery walls. It is commonly reported as systolic over diastolic pressure.
Carte 104
Question
What do coronary arteries supply?
Réponse
The heart muscle itself. Blocked coronary blood flow can deprive myocardium of oxygen.
Carte 105
Question
Which major vessels return systemic blood to the right atrium?
Réponse
The superior and inferior venae cavae. The superior vessel drains the upper body; the inferior drains the lower body.
Carte 106
Question
What is the respiratory system's primary gas-exchange function?
Réponse
Bringing oxygen into the body and removing carbon dioxide. Ventilation moves air, while diffusion exchanges gases.
Carte 107
Question
What is the airflow sequence from the pharynx to the gas-exchange surfaces?
Réponse
Pharynx, larynx, trachea, bronchi, bronchioles, alveoli. Each branch conducts air deeper into the lungs.
Carte 108
Question
Where does most gas exchange occur in the lungs?
Réponse
Across the alveolar-capillary membrane. Thin walls and a large surface area shorten diffusion distance.
Carte 109
Question
What does the diaphragm do during quiet inhalation?
Réponse
It contracts and moves downward. Thoracic volume rises, lung pressure falls, and air flows inward.
Carte 110
Question
Why does oxygen move from alveoli into pulmonary capillaries?
Réponse
Its partial pressure is higher in alveolar air than in incoming blood. Oxygen diffuses down that gradient.
Carte 111
Question
What drives quiet exhalation?
Réponse
Elastic recoil after inspiratory muscles relax. Thoracic volume falls and pressure pushes air outward.
Carte 112
Question
What is the pleura?
Réponse
A double membrane surrounding each lung. A thin fluid layer reduces friction during breathing.
Carte 113
Question
How is most oxygen transported in blood?
Réponse
Bound to hemoglobin in red blood cells. Only a small amount dissolves directly in plasma.
Carte 114
Question
Why does carbon dioxide move from pulmonary blood into alveoli?
Réponse
Its partial pressure is higher in incoming blood than in alveolar air. It diffuses down that gradient for exhalation.
Carte 115
Question
What helps keep swallowed material out of the airway?
Réponse
The epiglottis and coordinated swallowing reflexes. The laryngeal opening is protected as food passes.
Carte 116
Question
How does the conducting airway remove trapped particles?
Réponse
Mucus traps them, and cilia move the mucus toward the throat. This is the mucociliary escalator.
Carte 117
Question
In what form is most carbon dioxide transported in blood?
Réponse
As bicarbonate ions. Red blood cells help convert carbon dioxide and water into bicarbonate.
Carte 118
Question
Which blood change is a strong normal stimulus to increase breathing?
Réponse
A rise in carbon dioxide and the associated fall in pH. Brainstem centers adjust ventilation in response.
Carte 119
Question
Why must alveoli receive both air and blood?
Réponse
Gas exchange needs ventilation and perfusion. Air without blood flow, or blood without airflow, cannot exchange gases effectively.
Carte 120
Question
Why does ventilation increase during exercise?
Réponse
Active tissues use more oxygen and produce more carbon dioxide. Faster, deeper breathing helps meet that demand.
Carte 121
Question
What are the digestive system's core functions?
Réponse
Ingestion, digestion, absorption, and elimination. Movement and secretion support those processes.
Carte 122
Question
What is the alimentary-canal sequence after the mouth?
Réponse
Pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus. Food passes through this continuous tube.
Carte 123
Question
What is mechanical digestion?
Réponse
Physical breakdown and mixing of food without changing its molecules. Chewing and stomach churning are examples.
Carte 124
Question
What are two major functions of the stomach?
Réponse
It stores and mixes food and begins substantial protein digestion. Acid denatures proteins, converts pepsinogen to pepsin, and provides the low pH pepsin needs.
Carte 125
Question
Where does most nutrient absorption occur?
Réponse
The small intestine. Folds, villi, and microvilli create a large absorptive surface.
Carte 126
Question
Which nutrient does salivary amylase begin digesting in the mouth?
Réponse
Carbohydrates, especially starch. Salivary amylase breaks starch into smaller carbohydrates.
Carte 127
Question
What is chemical digestion?
Réponse
Enzymatic breakdown of large food molecules into absorbable units. Chemical bonds are changed during the process.
Carte 128
Question
What is peristalsis?
Réponse
Wave-like smooth-muscle contractions that move material forward. It occurs throughout much of the digestive tract.
Carte 129
Question
What is a main function of the large intestine?
Réponse
Absorbing water and electrolytes and forming feces. Resident microbes also process some undigested material.
Carte 130
Question
What digestive product does the liver make?
Réponse
Bile. Bile salts help disperse dietary fat into smaller droplets.
Carte 131
Question
What does a digestive sphincter do?
Réponse
It regulates movement between regions of the digestive tract. Circular muscle contracts to close a passage.
Carte 132
Question
What does the pancreas release into the small intestine?
Réponse
Digestive enzymes and bicarbonate-rich fluid. Bicarbonate helps neutralize acidic material from the stomach.
Carte 133
Question
How do intestinal villi improve absorption?
Réponse
They increase surface area. Each villus contains blood capillaries and a lymphatic lacteal for transported nutrients.
Carte 134
Question
What is the gallbladder's role?
Réponse
It stores and concentrates bile. It releases bile into the small intestine when fatty food arrives.
Carte 135
Question
Which macronutrient's absorbed products usually enter intestinal lacteals before reaching the blood?
Réponse
Most dietary lipids. Their absorbed products travel through lymph before entering the bloodstream.
Carte 136
Question
Which accessory organs help digestion without food passing through them?
Réponse
The teeth, tongue, salivary glands, liver, gallbladder, and pancreas. Teeth and the tongue act mechanically; the other accessory organs add or store digestive secretions.
Carte 137
Question
What organs make up the urinary system?
Réponse
The kidneys, ureters, urinary bladder, and urethra. Kidneys make urine; the remaining organs transport, store, and release it.
Carte 138
Question
What is a nephron?
Réponse
The kidney's functional unit. It filters blood and adjusts the filtrate to form urine.
Carte 139
Question
Where does blood filtration begin in a nephron?
Réponse
At the renal corpuscle. Pressure pushes water and small solutes from glomerular capillaries into the capsule.
Carte 140
Question
What moves urine from a kidney to the bladder?
Réponse
A ureter. Smooth-muscle contractions propel urine along the tube.
Carte 141
Question
What is the urinary bladder's main role?
Réponse
Temporary urine storage. Stretch receptors help trigger the urge to urinate as it fills.
Carte 142
Question
Which structure carries urine from the bladder out of the body?
Réponse
The urethra. It is distinct from the ureters that enter the bladder.
Carte 143
Question
What is tubular reabsorption?
Réponse
Movement of useful substances from nephron fluid back into blood. Water, glucose, and ions are common examples.
Carte 144
Question
What is the glomerulus?
Réponse
A capillary tuft that filters blood in the renal corpuscle. Cells and most large proteins normally remain in circulation.
Carte 145
Question
How does more ADH change urine?
Réponse
It makes urine more concentrated and lowers its volume. More water is reabsorbed from the collecting ducts.
Carte 146
Question
What path does filtrate follow after entering the glomerular capsule?
Réponse
Proximal convoluted tubule → nephron loop → distal convoluted tubule → collecting duct. The collecting duct receives forming urine from multiple nephrons.
Carte 147
Question
What is tubular secretion?
Réponse
Movement of selected substances from blood into nephron fluid. It helps eliminate wastes and regulate ions and pH.
Carte 148
Question
Besides removing waste, what does the urinary system regulate?
Réponse
Water, electrolytes, acid-base balance, and blood volume. Kidney hormones also affect blood pressure and red-cell production.
Carte 149
Question
Why does dehydration usually reduce urine volume?
Réponse
The body conserves water by increasing renal reabsorption. ADH is an important signal in this response.
Carte 150
Question
Why do the kidneys receive a large blood flow?
Réponse
They must continuously filter plasma and regulate its composition. High flow supports waste removal and homeostasis.
Carte 151
Question
What is lymph?
Réponse
Interstitial fluid that has entered lymphatic vessels. It eventually returns to the bloodstream.
Carte 152
Question
What is innate immunity?
Réponse
Rapid, nonspecific defense present before a particular exposure. Barriers, inflammation, and several immune cells contribute.
Carte 153
Question
What is a major function of lymph nodes?
Réponse
Filtering lymph and providing sites for immune-cell activation. Swelling can reflect an active immune response.
Carte 154
Question
What does the spleen filter?
Réponse
Blood. It removes aged blood cells and supports immune responses to blood-borne antigens.
Carte 155
Question
What is a key function of B lymphocytes?
Réponse
Producing antibody-secreting cells and memory cells. Antibodies bind specific antigens.
Carte 156
Question
What distinguishes adaptive immunity?
Réponse
It targets specific antigens and develops memory. Later exposure can trigger a faster, stronger response.
Carte 157
Question
Which lymphatic organ is important for T-cell maturation?
Réponse
The thymus. It is most active early in life.
Carte 158
Question
What is the body's first physical barrier against many pathogens?
Réponse
Intact skin and mucous membranes. Their secretions and normal microbes add protection.
Carte 159
Question
What is a key function of T lymphocytes?
Réponse
Coordinating immune responses or killing infected cells. Different T-cell types perform different roles.
Carte 160
Question
What does an antibody bind?
Réponse
A specific antigen. Binding can neutralize a target or mark it for other immune defenses.
Carte 161
Question
What is the purpose of inflammation after tissue injury?
Réponse
To contain damage, recruit defenses, and begin repair. Redness, heat, swelling, and pain can accompany it.
Carte 162
Question
Why is a second adaptive response often faster than the first?
Réponse
Memory lymphocytes remain after the first exposure. They respond quickly when the same antigen appears again.
Carte 163
Question
What does a phagocyte do?
Réponse
It engulfs particles, microbes, or debris. Neutrophils and macrophages are important examples.
Carte 164
Question
How does vaccination support adaptive immunity?
Réponse
It safely exposes the immune system to antigen information. This promotes memory without requiring the full disease.
Carte 165
Question
Why is lymphatic fluid return important?
Réponse
It prevents excess interstitial fluid from accumulating. Lymphatic vessels return fluid and leaked proteins to blood.
Carte 166
Question
What structures belong to the integumentary system?
Réponse
Skin, hair, nails, sweat glands, and sebaceous glands. Together they form the body's outer covering.
Carte 167
Question
What is the epidermis?
Réponse
The outer epithelial layer of skin. It is avascular and contains protective keratinized cells.
Carte 168
Question
How does sweating cool the body?
Réponse
Evaporation removes heat from the skin. Skin blood-flow changes also help regulate heat loss.
Carte 169
Question
What is a major role of melanin in skin?
Réponse
Absorbing some ultraviolet radiation. It also contributes to skin and hair color.
Carte 170
Question
How does skin contribute to sensation?
Réponse
Sensory receptors detect touch, pressure, pain, and temperature. Nerves carry that information to the CNS.
Carte 171
Question
What is the dermis?
Réponse
The connective-tissue layer beneath the epidermis. It contains vessels, nerves, glands, and hair follicles.
Carte 172
Question
How does skin support vitamin D production?
Réponse
Ultraviolet light starts conversion of a skin molecule into a vitamin D precursor. The liver and kidneys complete activation.
Carte 173
Question
Why does a deep skin wound bleed but a shallow epidermal scrape may not?
Réponse
Blood vessels are in the dermis, not the epidermis. A wound must reach vascular tissue to damage them.
Carte 174
Question
What is a gamete?
Réponse
A haploid reproductive cell. Human sperm and oocytes each carry 23 chromosomes.
Carte 175
Question
What are the testes' two main reproductive functions?
Réponse
Producing sperm and secreting testosterone. Sperm develop in seminiferous tubules.
Carte 176
Question
What tube carries sperm from the epididymis toward the ejaculatory duct?
Réponse
The ductus, or vas, deferens. Smooth muscle propels sperm during ejaculation.
Carte 177
Question
What is ovulation?
Réponse
Release of a secondary oocyte from an ovary. A surge in luteinizing hormone helps trigger it.
Carte 178
Question
Where does fertilization usually occur?
Réponse
In a uterine tube. The early embryo then travels toward the uterus.
Carte 179
Question
What are the ovaries' two main reproductive functions?
Réponse
Producing oocytes and secreting sex hormones. Estrogen and progesterone help regulate the reproductive cycle.
Carte 180
Question
What is the uterus' main reproductive role?
Réponse
Supporting implantation and development of an embryo and fetus. Its muscular wall also contracts during birth.
Carte 181
Question
What causes menstruation when pregnancy does not occur?
Réponse
Falling ovarian hormones allow the uterine lining to shed. A new cycle then begins.
Carte 182
Question
How does a sperm cell's structure support its function?
Réponse
Its flagellum provides movement, and its head carries DNA plus enzymes used during fertilization. Mitochondria supply energy in the midpiece.
Carte 183
Question
What is the placenta's exchange role?
Réponse
It allows gases, nutrients, and wastes to move between maternal and fetal circulations. Their blood normally does not mix directly.
Carte 184
Question
Why is meiosis necessary for sexual reproduction?
Réponse
It halves chromosome number in gametes. Fertilization then restores the diploid number.
Carte 185
Question
How do sex hormones regulate reproductive control pathways?
Réponse
They usually feed back on the hypothalamus and pituitary. This adjusts release of hormones that act on the gonads.
Carte 186
Question
What does cell theory state?
Réponse
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.
Carte 187
Question
What is the defining structural feature of a prokaryotic cell?
Réponse
It lacks a membrane-bound nucleus. Its DNA occupies a nucleoid region.
Carte 188
Question
What is the cell membrane's main role?
Réponse
Regulating movement between the cell and its environment. Its phospholipid bilayer is selectively permeable.
Carte 189
Question
What is the nucleus' main role?
Réponse
Storing most of a eukaryotic cell's DNA. Nuclear pores regulate exchange with the cytoplasm.
Carte 190
Question
Where are proteins assembled?
Réponse
At ribosomes. Ribosomes may float in cytosol or attach to rough endoplasmic reticulum.
Carte 191
Question
What distinguishes a eukaryotic cell from a prokaryotic cell?
Réponse
A eukaryotic cell has a membrane-bound nucleus and other membrane-bound organelles. Animals, plants, fungi, and protists are eukaryotes.
Carte 192
Question
What is a mitochondrion's main function?
Réponse
Producing most cellular ATP through aerobic respiration. Its inner membrane provides a large reaction surface.
Carte 193
Question
What does rough endoplasmic reticulum mainly produce?
Réponse
Proteins for secretion, membranes, or organelles. Ribosomes on its surface make the proteins.
Carte 194
Question
Which organelle carries out photosynthesis in plants and algae?
Réponse
The chloroplast. It converts light energy into chemical energy stored in organic molecules.
Carte 195
Question
What does the Golgi apparatus do?
Réponse
It modifies, sorts, and packages cell products. Vesicles carry those products to their destinations.
Carte 196
Question
What is a lysosome's role?
Réponse
Digesting worn cell parts and engulfed material. Its enzymes work best in an acidic interior.
Carte 197
Question
What are major functions of smooth endoplasmic reticulum?
Réponse
Lipid synthesis, detoxification, and calcium storage. Its membrane lacks attached ribosomes.
Carte 198
Question
What does the cytoskeleton provide?
Réponse
Cell shape, internal organization, movement, and transport tracks. It is built from protein filaments.
Carte 199
Question
What is diffusion?
Réponse
Net movement from higher to lower concentration. It is passive and continues until dynamic equilibrium is reached.
Carte 200
Question
What happens to an animal cell in a strongly hypotonic solution?
Réponse
Water enters and the cell swells. Without a cell wall, it may burst.
Carte 201
Question
What happens during interphase?
Réponse
The cell grows, performs normal functions, and copies its DNA. Interphase precedes mitotic division.
Carte 202
Question
What is the result of mitosis followed by cytokinesis?
Réponse
Two genetically similar daughter cells. Chromosome number is normally preserved.
Carte 203
Question
What is osmosis?
Réponse
Diffusion of water across a selectively permeable membrane. Water moves toward the side with more nonpenetrating solute.
Carte 204
Question
What happens to an animal cell in a hypertonic solution?
Réponse
Water leaves and the cell shrinks. The external solution has a higher effective solute concentration.
Carte 205
Question
Why are cells generally small?
Réponse
A high surface-area-to-volume ratio supports efficient exchange. Volume grows faster than surface area as a cell enlarges.
Carte 206
Question
What is cytokinesis?
Réponse
Division of the cytoplasm. It separates one cell into two after nuclear division.
Carte 207
Question
How does active transport differ from passive transport?
Réponse
It uses energy to move substances against a gradient. Passive transport moves down a gradient without direct energy input.
Carte 208
Question
What happens to an animal cell in an isotonic solution?
Réponse
There is no net water movement. Water still crosses in both directions at equal rates.
Carte 209
Question
Which structures are typical of plant cells but not animal cells?
Réponse
A cellulose cell wall, chloroplasts, and a large central vacuole. Both cell types have membranes, nuclei, and mitochondria.
Carte 210
Question
How do cells contribute to a multicellular organism's organization?
Réponse
Specialized cells form tissues, tissues form organs, and organs form systems. Division of labor supports complex functions.
Carte 211
Question
What is DNA's primary biological role?
Réponse
Storing hereditary information. Its nucleotide sequence contains instructions used to build functional RNA and proteins.
Carte 212
Question
What are the three parts of a DNA nucleotide?
Réponse
A deoxyribose sugar, a phosphate group, and a nitrogenous base. Nucleotides link to form each strand.
Carte 213
Question
Which bases pair in double-stranded DNA?
Réponse
Adenine with thymine, and cytosine with guanine. Hydrogen bonds hold complementary strands together.
Carte 214
Question
How does RNA differ from DNA?
Réponse
RNA usually has ribose, uses uracil instead of thymine, and is usually single-stranded. Several RNA types help express genes.
Carte 215
Question
What is a gene?
Réponse
A DNA sequence that contributes to a functional product. The product may be a protein or a functional RNA.
Carte 216
Question
What is a chromosome?
Réponse
A long DNA molecule packaged with proteins. It contains many genes and other sequences.
Carte 217
Question
What is DNA replication?
Réponse
Copying DNA before cell division. Each new DNA molecule contains one old strand and one newly made strand.
Carte 218
Question
What is the usual flow of information from a protein-coding gene?
Réponse
DNA to RNA to protein. Transcription makes RNA; translation builds the polypeptide.
Carte 219
Question
What happens during transcription?
Réponse
RNA is synthesized from a DNA template. For a protein-coding gene, that RNA functions as or is processed into messenger RNA.
Carte 220
Question
What does messenger RNA carry?
Réponse
A copy of coding information from DNA to a ribosome. Its codons specify the amino-acid sequence.
Carte 221
Question
What is a codon?
Réponse
A three-nucleotide sequence in mRNA. Most codons specify an amino acid; some signal start or stop.
Carte 222
Question
What is the usual role of the AUG codon?
Réponse
It starts translation and specifies methionine. The ribosome uses it to establish the reading frame.
Carte 223
Question
What happens during translation?
Réponse
A ribosome reads mRNA and joins amino acids into a polypeptide. Transfer RNAs match codons with amino acids.
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Carte 224
Question
What is transfer RNA's role in protein synthesis?
Réponse
It carries an amino acid and matches its anticodon to an mRNA codon. This places the correct amino acid in sequence.
Carte 225
Question
What is an anticodon?
Réponse
A three-base sequence on tRNA complementary to an mRNA codon. Pairing helps decode the message.
Carte 226
Question
What is a mutation?
Réponse
A change in a DNA sequence. Its effect may be harmful, neutral, or beneficial depending on location and context.
Carte 227
Question
Why can a one-base insertion in a coding sequence have a large effect?
Réponse
It can shift the reading frame. Every downstream codon may change until a stop signal appears.
Carte 228
Question
Why can changing one amino acid alter a protein's function?
Réponse
Amino-acid sequence helps determine folding and shape. Shape controls many protein interactions.
Carte 229
Question
What is ribosomal RNA's role in protein synthesis?
Réponse
It forms the structural and catalytic core of ribosomes. Ribosomal RNA helps align translation components and catalyzes peptide-bond formation.
Carte 230
Question
Why can different cell types contain the same DNA but perform different jobs?
Réponse
They express different sets of genes. Different proteins give cells different structures and functions.
Carte 231
Question
Which mutation can be passed to offspring?
Réponse
A mutation present in a gamete-forming lineage. A mutation limited to ordinary body cells is not inherited through reproduction.
Carte 232
Question
What is an allele?
Réponse
An alternative version of a gene. Diploid individuals usually carry two alleles for each autosomal gene.
Carte 233
Question
What is genotype?
Réponse
An organism's allele combination for a gene or set of genes. Genotype contributes to phenotype.
Carte 234
Question
What does homozygous mean?
Réponse
Having two identical alleles for a gene. Examples include AA and aa.
Carte 235
Question
What makes an allele dominant in a simple Mendelian trait?
Réponse
One copy is enough for its phenotype to appear in a heterozygote. Dominant does not mean common or beneficial.
Carte 236
Question
What does Mendel's law of segregation describe?
Réponse
The two alleles for a gene separate during gamete formation. Each gamete receives one allele.
Carte 237
Question
What is phenotype?
Réponse
An observable trait or characteristic. It can reflect genotype, environment, and their interaction.
Carte 238
Question
What does heterozygous mean?
Réponse
Having two different alleles for a gene. An example is Aa.
Carte 239
Question
When does a recessive phenotype usually appear in a simple autosomal trait?
Réponse
When both alleles are recessive. A heterozygote carries the allele without showing that phenotype.
Carte 240
Question
When does independent assortment apply most clearly?
Réponse
When genes are on different chromosomes or far apart on the same chromosome. Their allele pairs enter gametes independently.
Carte 241
Question
What does a Punnett square predict?
Réponse
Expected offspring genotype probabilities from specified parental gametes. It does not guarantee outcomes in a small family.
Carte 242
Question
For Aa × Aa, what is the chance of an aa offspring?
Réponse
One fourth, or 25%. The genotype ratio is expected to be 1 AA : 2 Aa : 1 aa.
Carte 243
Question
For Aa × Aa with complete dominance, what phenotypic ratio is expected?
Réponse
Three dominant-phenotype offspring to one recessive-phenotype offspring. This is a probability across many offspring.
Carte 244
Question
How can a test cross reveal the genotype behind a dominant phenotype?
Réponse
Cross the individual with a homozygous recessive partner. Recessive offspring show that the unknown parent carried a recessive allele.
Carte 245
Question
What happens in incomplete dominance?
Réponse
A heterozygote has an intermediate phenotype. Neither allele fully masks the other.
Carte 246
Question
How is the probability of two independent genetic events both occurring found?
Réponse
Multiply their individual probabilities. This is the product rule.
Carte 247
Question
What does a pedigree show?
Réponse
How a trait appears across generations of a family. Its pattern can suggest a mode of inheritance.
Carte 248
Question
Why can two parents have offspring ratios that differ from a Punnett-square expectation?
Réponse
Each fertilization is a chance event. Expected ratios become more apparent with larger numbers of offspring.
Carte 249
Question
What happens in codominance?
Réponse
Both alleles are distinctly expressed in a heterozygote. The AB blood type is a common example.
Carte 250
Question
What are major roles of carbohydrates?
Réponse
Providing quick energy, storing energy, and forming some structures. Monosaccharides are their basic building blocks.
Carte 251
Question
What is a monomer?
Réponse
A small building block that can join with others to form a larger molecule. Glucose, amino acids, and nucleotides are examples in different classes.
Carte 252
Question
What happens in a dehydration-synthesis reaction?
Réponse
Monomers join while water is removed. The reaction builds a larger biological molecule.
Carte 253
Question
What does an enzyme do?
Réponse
It lowers activation energy and speeds a reaction without being consumed. Its shape helps it bind specific substrates.
Carte 254
Question
What are major roles of lipids?
Réponse
Long-term energy storage, membranes, insulation, and signaling. Lipids are mostly nonpolar and do not mix well with water.
Carte 255
Question
What does it mean for a protein to denature?
Réponse
Its normal shape is disrupted. Heat, extreme pH, or chemicals can reduce its function.
Carte 256
Question
What happens during hydrolysis?
Réponse
Water is used to split a larger molecule into smaller units. Digestion often uses hydrolysis reactions.
Carte 257
Question
Why do phospholipids form bilayers in water?
Réponse
Their hydrophilic heads interact with water while hydrophobic tails turn inward. This arrangement forms cell-membrane structure.
Carte 258
Question
What are proteins built from?
Réponse
Amino acids linked by peptide bonds. Their folded shapes support enzymes, transport, signaling, structure, and movement.
Carte 259
Question
How do starch and glycogen compare?
Réponse
Both store glucose; plants use starch and animals use glycogen. Their branching patterns differ.
Carte 260
Question
How do saturated and unsaturated fatty acids differ?
Réponse
Saturated fatty acids lack carbon-carbon double bonds; unsaturated ones have one or more. Double bonds often introduce bends.
Carte 261
Question
What immediate energy-carrying molecule powers many cell processes?
Réponse
ATP. Energy released from nutrients can be transferred into ATP's phosphate bonds.
Carte 262
Question
What are nucleic acids built from?
Réponse
Nucleotides. DNA stores hereditary information, while RNA performs several roles in gene expression.
Carte 263
Question
Which elements are common in all four major biological macromolecule classes?
Réponse
Carbon, hydrogen, and oxygen. Nitrogen and phosphorus occur prominently in some classes.
Carte 264
Question
Why is three-dimensional shape important for macromolecules?
Réponse
Shape determines many interactions and functions. A changed shape can prevent a molecule from binding its target.
Carte 265
Question
What are triglycerides built from?
Réponse
One glycerol molecule and three fatty acids. They join through ester bonds to form a common energy-storage lipid.
Carte 266
Question
What is a pathogen?
Réponse
An agent capable of causing disease. Not every microorganism is pathogenic.
Carte 267
Question
What type of cell is a bacterium?
Réponse
A prokaryotic cell. Bacteria usually reproduce by binary fission.
Carte 268
Question
What cell type do fungi have?
Réponse
Eukaryotic cells. Some fungi are unicellular yeasts, while others form multicellular filaments.
Carte 269
Question
What does disease transmission describe?
Réponse
How an infectious agent moves to a susceptible host. Routes include contact, droplets, airborne spread, food, water, and vectors.
Carte 270
Question
What is a biological vector?
Réponse
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.
Carte 271
Question
Why are viruses dependent on host cells?
Réponse
They lack the complete machinery for reproduction and metabolism. They use host components to make new virus particles.
Carte 272
Question
What is a protist?
Réponse
A diverse eukaryote that is not classified as an animal, plant, or fungus. Some protists cause disease, while many do not.
Carte 273
Question
Why do antibiotics not treat viral infections?
Réponse
They target bacterial structures or processes that viruses lack. Antiviral drugs use different targets.
Carte 274
Question
How can normal microbiota protect a host?
Réponse
They occupy space and use resources that pathogens might otherwise exploit. Some also support digestion or immune development.
Carte 275
Question
How does sterilization differ from disinfection?
Réponse
Sterilization destroys or removes all microbial life, including resistant forms; disinfection reduces pathogens on objects. The required method depends on use.
Carte 276
Question
How do infection and disease differ?
Réponse
Infection means an agent is established in a host; disease means normal function is impaired and signs or symptoms occur. Infection may be asymptomatic.
Carte 277
Question
How can breaking a transmission route reduce infectious disease?
Réponse
It interrupts the chain connecting a source with a susceptible host. Hand hygiene, clean water, ventilation, and vector control target different links.
Carte 278
Question
What is an atom?
Réponse
The smallest unit of an element that retains that element's chemical identity. Atoms contain a nucleus surrounded by electrons.
Carte 279
Question
What charge and location does an electron have?
Réponse
Negative charge in the electron cloud around the nucleus. Electrons drive most chemical bonding.
Carte 280
Question
Why are valence electrons important?
Réponse
They participate most directly in bonding and reactions. Their arrangement helps predict chemical behavior.
Carte 281
Question
What do elements in the same periodic-table group often share?
Réponse
Similar valence-electron patterns and chemical properties. A group is a vertical column.
Carte 282
Question
What is an ion?
Réponse
An atom or group of atoms with a net electric charge. Its total numbers of protons and electrons are unequal.
Carte 283
Question
What charge and location does a proton have?
Réponse
Positive charge in the nucleus. The number of protons determines the element.
Carte 284
Question
What does an element's atomic number equal?
Réponse
Its number of protons. A neutral atom has the same number of electrons.
Carte 285
Question
How does a neutral atom form a cation?
Réponse
By losing one or more electrons. It has more protons than electrons and a positive charge.
Carte 286
Question
An atom has 8 protons. How many electrons does it have if it is neutral?
Réponse
Eight electrons. Neutral atoms have equal positive and negative charges.
Carte 287
Question
What charge and location does a neutron have?
Réponse
No electric charge, in the nucleus. Neutron number can vary among isotopes of an element.
Carte 288
Question
What does mass number equal?
Réponse
Protons plus neutrons in one atom. It is a whole number for a specific isotope.
Carte 289
Question
How does a neutral atom form an anion?
Réponse
By gaining one or more electrons. It has more electrons than protons and a negative charge.
Carte 290
Question
What does a period represent on the periodic table?
Réponse
A horizontal row. Moving across a period changes proton number one element at a time.
Carte 291
Question
What are isotopes?
Réponse
Atoms of the same element with different numbers of neutrons. They have the same atomic number but different mass numbers.
Carte 292
Question
What is matter?
Réponse
Anything that has mass and occupies space. Solids, liquids, gases, and plasma are forms of matter.
Carte 293
Question
What distinguishes a solid from a liquid or gas?
Réponse
A solid has a definite shape and volume. Its particles vibrate around relatively fixed positions.
Carte 294
Question
What is a physical change?
Réponse
A change in form or state without changing chemical identity. Melting and cutting are examples.
Carte 295
Question
What is a physical property?
Réponse
A characteristic observed without changing a substance's identity. Density, color, and melting point are examples.
Carte 296
Question
How does an element differ from a compound?
Réponse
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.
Carte 297
Question
What distinguishes a liquid?
Réponse
It has a definite volume but takes the shape of its container. Its particles remain close while moving past one another.
Carte 298
Question
What is a chemical change?
Réponse
A process that forms one or more substances with new chemical identities. Bond rearrangement occurs.
Carte 299
Question
What is a chemical property?
Réponse
A substance's ability to undergo a particular chemical change. Flammability and reactivity with acid are examples.
Carte 300
Question
Which phase changes connect solids and liquids?
Réponse
Melting changes a solid to a liquid; freezing changes a liquid to a solid. These are opposite physical changes.
Carte 301
Question
How does a pure substance differ from a mixture?
Réponse
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.
Carte 302
Question
What distinguishes a gas?
Réponse
It has neither a definite shape nor a definite volume. It expands to fill its container.
Carte 303
Question
What is the formula for density?
Réponse
Density = mass ÷ volume. Density is an intensive property.
Carte 304
Question
Which phase changes connect liquids and gases?
Réponse
Vaporization changes a liquid to a gas; condensation changes a gas to a liquid. Evaporation is vaporization at a liquid's surface.
Carte 305
Question
What is a mixture?
Réponse
Two or more substances physically combined in variable proportions. Its components retain their chemical identities.
Carte 306
Question
How do intensive and extensive properties differ?
Réponse
Intensive properties do not depend on sample amount; extensive properties do. Density and temperature are intensive, while mass and volume are extensive.
Carte 307
Question
A 20 g sample occupies 5 mL. What is its density?
Réponse
4 g/mL. Divide 20 g by 5 mL.
Carte 308
Question
Which phase changes connect solids and gases directly?
Réponse
Sublimation changes a solid to a gas; deposition changes a gas to a solid. Neither transition passes through the liquid state.
Carte 309
Question
How do homogeneous and heterogeneous mixtures differ?
Réponse
A homogeneous mixture is uniform throughout; a heterogeneous mixture is not. A solution is homogeneous.
Carte 310
Question
Where are reactants and products written in a chemical equation?
Réponse
Reactants are on the left; products are on the right. The arrow shows the direction represented.
Carte 311
Question
Why must a chemical equation be balanced?
Réponse
Atoms are conserved in ordinary chemical reactions. Each element must have the same atom count on both sides.
Carte 312
Question
What does a coefficient in a chemical equation change?
Réponse
The number of whole particles or moles represented. It multiplies every atom in the following formula.
Carte 313
Question
Why should subscripts not be changed when balancing an equation?
Réponse
Changing a subscript changes the substance's identity. Balancing changes coefficients only.
Carte 314
Question
What coefficients balance H₂ + O₂ → H₂O?
Réponse
2, 1, 2: 2H₂ + O₂ → 2H₂O. Both sides then contain four hydrogen atoms and two oxygen atoms.
Carte 315
Question
What pattern defines a synthesis reaction?
Réponse
Two or more reactants form a more complex product. A general pattern is A + B → AB.
Carte 316
Question
What are typical products when a hydrocarbon burns completely in oxygen?
Réponse
Carbon dioxide and water. Incomplete combustion can produce carbon monoxide or carbon.
Carte 317
Question
What is the net ionic equation for a typical strong acid–strong base neutralization?
Réponse
H⁺(aq) + OH⁻(aq) → H₂O(l). The remaining ions are spectators and do not appear in the net ionic equation.
Carte 318
Question
What is a precipitate?
Réponse
An insoluble solid that forms from substances in solution. Its appearance can signal a chemical reaction.
Carte 319
Question
What pattern defines a decomposition reaction?
Réponse
One compound breaks into simpler products. A general pattern is AB → A + B.
Carte 320
Question
What is an exothermic reaction?
Réponse
A reaction that releases heat to the surroundings. The surroundings often warm.
Carte 321
Question
What occurs in an oxidation-reduction reaction?
Réponse
Electrons transfer or atoms change oxidation state. Oxidation is electron loss; reduction is electron gain.
Carte 322
Question
What is activation energy?
Réponse
The minimum energy barrier reactants must overcome to react. Catalysts lower this barrier.
Carte 323
Question
Which observations can provide evidence of a chemical reaction?
Réponse
Gas formation, a precipitate, sustained color change, light, or temperature change. No single sign proves a reaction without context.
Carte 324
Question
What is an endothermic reaction?
Réponse
A reaction that absorbs heat from the surroundings. The surroundings may cool.
Carte 325
Question
Why does raising temperature usually speed a reaction?
Réponse
Particles collide more often and with greater energy. More collisions overcome activation energy.
Carte 326
Question
Why can higher reactant concentration increase reaction rate?
Réponse
More reactant particles occupy a given volume. This raises collision frequency.
Carte 327
Question
Why does powdered solid often react faster than one large piece?
Réponse
Powder exposes more surface area. More particles are available for collisions.
Carte 328
Question
How does a catalyst speed a reaction?
Réponse
It provides a pathway with lower activation energy. The catalyst is regenerated rather than consumed overall.
Carte 329
Question
How can increasing pressure affect a reaction between gases?
Réponse
It can increase rate by bringing gas particles closer together. Collision frequency rises when volume falls.
Carte 330
Question
What does a reaction inhibitor do?
Réponse
It slows a reaction. It may block a pathway, interfere with a catalyst, or remove reactive intermediates.
Carte 331
Question
Why can very high temperature slow an enzyme-catalyzed reaction?
Réponse
The enzyme can denature and lose its active shape. Moderate warming helps only within the enzyme's stable range.
Carte 332
Question
What is dynamic equilibrium?
Réponse
Forward and reverse reactions continue at equal rates. Concentrations remain constant even though particles still react.
Carte 333
Question
Does a catalyst change the final equilibrium amounts?
Réponse
No. It speeds forward and reverse reactions, so equilibrium is reached sooner without changing its position.
Carte 334
Question
At equilibrium, what usually happens when the concentration of a dissolved or gaseous reactant increases?
Réponse
The system shifts toward consuming some added reactant. It forms more product until a new equilibrium is reached.
Carte 335
Question
What is a solution?
Réponse
A homogeneous mixture. Its components are uniformly distributed at the molecular or ionic level.
Carte 336
Question
How do solute and solvent differ?
Réponse
The solute is dissolved; the solvent is the dissolving medium. The solvent is often present in greater amount.
Carte 337
Question
What does aqueous mean in chemistry?
Réponse
Dissolved in water. The symbol (aq) marks an aqueous species in an equation.
Carte 338
Question
What does concentration describe?
Réponse
The amount of solute in a given amount of solution or solvent. Different units express it in different ways.
Carte 339
Question
What is molarity?
Réponse
Moles of solute per liter of solution. Its unit is mol/L, written M.
Carte 340
Question
What is the molarity of 0.50 mol solute in 2.0 L of solution?
Réponse
0.25 M. Divide 0.50 mol by 2.0 L.
Carte 341
Question
What stays constant when water is added to dilute a solution without reaction?
Réponse
The moles of solute. Volume increases and concentration decreases.
Carte 342
Question
Which equation relates concentration and volume before and after a dilution?
Réponse
M₁V₁ = M₂V₂. It follows from conserving the amount of solute.
Carte 343
Question
What is solubility?
Réponse
The maximum concentration of a solute that can be achieved in a solution at equilibrium under specified conditions. Temperature and the substances involved matter.
Carte 344
Question
What is a saturated solution?
Réponse
A solution holding the maximum dissolved solute at those conditions. Extra solute remains undissolved at equilibrium.
Carte 345
Question
What is an electrolyte?
Réponse
A substance that produces mobile ions in solution and conducts electricity. Soluble ionic compounds are common examples.
Carte 346
Question
What does 'like dissolves like' predict?
Réponse
Substances with similar polarity tend to mix well. Polar solvents favor polar or ionic solutes; nonpolar solvents favor nonpolar solutes.
Carte 347
Question
Does heating always increase solubility?
Réponse
No. Many solids become more soluble in water, but gases usually become less soluble as temperature rises.
Carte 348
Question
What is an unsaturated solution?
Réponse
A solution that can dissolve more solute at the stated conditions. It is below the solubility limit.
Carte 349
Question
What does a Brønsted-Lowry acid donate?
Réponse
A proton, H⁺. In water, acid behavior increases hydronium-ion concentration.
Carte 350
Question
What does pH describe?
Réponse
The hydronium-ion concentration on a logarithmic scale. Lower pH means higher hydronium concentration.
Carte 351
Question
At 25 °C, what pH range is acidic?
Réponse
Below 7. A neutral aqueous solution is pH 7 at this temperature.
Carte 352
Question
How does hydronium concentration change when pH drops by 1 unit?
Réponse
It increases tenfold. The pH scale is logarithmic.
Carte 353
Question
What does a Brønsted-Lowry base accept?
Réponse
A proton, H⁺. Many bases in water also increase hydroxide-ion concentration.
Carte 354
Question
At 25 °C, what is the relationship between pH and pOH?
Réponse
pH + pOH = 14. pOH is the negative base-10 logarithm of hydroxide-ion concentration; this relation applies to aqueous solutions at 25 °C.
Carte 355
Question
At 25 °C, what pH range is basic?
Réponse
Above 7. Basic solutions have less hydronium and more hydroxide than neutral water.
Carte 356
Question
What are typical products of a strong acid reacting with a strong base?
Réponse
Water and an ionic salt. Hydrogen ions and hydroxide ions combine to form water.
Carte 357
Question
What does strong mean for an acid or base?
Réponse
It produces its characteristic ions essentially completely in water. Strong acids ionize; soluble ionic strong bases dissociate. Strength is separate from concentration.
Carte 358
Question
What does a buffer do?
Réponse
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⁻.
Carte 359
Question
How does an acid-base indicator work?
Réponse
Its color depends on pH. The change occurs over a characteristic pH range.
Carte 360
Question
A solution has pH 9 at 25 °C. What is its pOH?
Réponse
5. Subtract the pH from 14.
Carte 361
Question
How does a concentrated weak acid differ from a dilute strong acid?
Réponse
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.
Carte 362
Question
What is the SI base unit of length?
Réponse
The meter (m). Centimeters and millimeters are decimal subdivisions of a meter.
Carte 363
Question
Which tool directly measures mass in a laboratory?
Réponse
A balance. A spring scale measures force, often reported as weight.
Carte 364
Question
What is the SI base unit of mass?
Réponse
The kilogram (kg). Laboratory mass is also commonly reported in grams.
Carte 365
Question
A student needs to measure about 35 mL of liquid and can choose a beaker or graduated cylinder. Which should they use?
Réponse
A graduated cylinder. Read the scale at eye level.
Carte 366
Question
What is the SI base unit of time?
Réponse
The second (s). Minutes and hours are accepted for many everyday uses.
Carte 367
Question
Where should the volume of a clear water-based liquid be read in a graduated cylinder?
Réponse
At the bottom of the meniscus. Keep your eye level with the liquid surface.
Carte 368
Question
What is the SI base unit of thermodynamic temperature?
Réponse
The kelvin (K). Degrees Celsius are widely used for laboratory and body temperatures.
Carte 369
Question
Which tool measures temperature?
Réponse
A thermometer. Its range and resolution should match the task.
Carte 370
Question
What factor does the metric prefix kilo- represent?
Réponse
One thousand, or 10³. One kilometer equals 1,000 meters.
Carte 371
Question
A ruler's smallest marking is 1 mm. To what place should a careful analog reading usually be estimated?
Réponse
One place beyond the smallest marking, when the scale allows it. The final digit is uncertain.
Carte 372
Question
What is measurement accuracy?
Réponse
Closeness to an accepted or true value. A systematic error can make precise measurements inaccurate.
Carte 373
Question
How do mass and weight differ?
Réponse
Mass is the amount of matter; weight is gravitational force on that mass. Mass stays constant when gravity changes, but weight does not.
Carte 374
Question
What factor does the metric prefix milli- represent?
Réponse
One thousandth, or 10⁻³. One milliliter is 0.001 liter.
Carte 375
Question
How can the volume of an irregular solid be measured with water?
Réponse
Use water displacement. Subtract the initial water volume from the final volume after submerging the object.
Carte 376
Question
What is measurement precision?
Réponse
Closeness of repeated measurements to one another. Precise results can still be consistently wrong.
Carte 377
Question
What is an instrument's resolution?
Réponse
The smallest change it can meaningfully display or distinguish. Higher resolution does not automatically guarantee accuracy.
Carte 378
Question
How many centimeters are in 2.5 meters?
Réponse
2.5 × 10² cm (250 cm). Multiply meters by the exact conversion factor 100 cm/m.
Carte 379
Question
Why must a numerical measurement include a unit?
Réponse
The unit identifies the quantity's scale. A bare number is ambiguous and cannot be compared reliably.
Carte 380
Question
What is a scientific observation?
Réponse
Information recorded with senses or instruments. It should be distinguished from an explanation of what was observed.
Carte 381
Question
What makes a hypothesis scientifically useful?
Réponse
It is testable and falsifiable. Evidence must be able to count against it.
Carte 382
Question
What is a scientific theory?
Réponse
A broad, well-supported explanation of natural phenomena. It is not a casual guess and can be revised with new evidence.
Carte 383
Question
Which claim is falsifiable: 'No possible observation could count against this treatment's effectiveness' or 'This treatment lowers mean temperature within one hour'?
Réponse
The claim that the treatment lowers mean temperature within one hour. An observation could count against it, so evidence can test it.
Carte 384
Question
What is an inference?
Réponse
A logical interpretation based on observations and prior knowledge. It goes beyond the raw measurement.
Carte 385
Question
How does a prediction relate to a hypothesis?
Réponse
It states an expected result if the hypothesis is correct. Experiments compare observed results with that expectation.
Carte 386
Question
How does a scientific law differ from a scientific theory?
Réponse
A law describes a consistent pattern; a theory explains how or why patterns occur. One does not mature into the other.
Carte 387
Question
What does reliability mean for a measurement or procedure?
Réponse
It produces consistent results under the same conditions. Repetition helps assess reliability.
Carte 388
Question
What does a correlation show?
Réponse
Two variables change together in a patterned way. Correlation alone does not establish that one causes the other.
Carte 389
Question
What is bias in scientific work?
Réponse
A systematic influence that pushes observations, selection, or interpretation in one direction. Good design tries to prevent or measure it.
Carte 390
Question
What is the purpose of scientific peer review?
Réponse
Independent experts evaluate methods, reasoning, and reporting before publication. It improves scrutiny but does not guarantee truth.
Carte 391
Question
What does validity ask about a study or measurement?
Réponse
Whether it measures or tests what it claims to measure or test. Consistency alone does not ensure validity.
Carte 392
Question
What evidence most strengthens a causal claim?
Réponse
A well-controlled experiment that manipulates the suspected cause. Random assignment reduces confounding, while independent replication tests whether the result holds with new data.
Carte 393
Question
What is a primary scientific source?
Réponse
A report of original methods, data, and results. A review article synthesizes many primary studies.
Carte 394
Question
How should an unexpected outlier be handled?
Réponse
Investigate and report it rather than deleting it automatically. Exclusion needs a documented scientific reason.
Carte 395
Question
What is a confounding variable?
Réponse
An outside factor related to both the suspected cause and the outcome. It can create a misleading association.
Carte 396
Question
Why should a sample represent the population of interest?
Réponse
Results generalize poorly when important groups are missing or overrepresented. Sampling method matters as much as size.
Carte 397
Question
What is a scientific model?
Réponse
A simplified representation used to explain or predict a system. A model is useful within its assumptions and limits.
Carte 398
Question
Why should measurements report uncertainty or reasonable precision?
Réponse
Every measurement has limits. Reporting more digits than the method supports creates false precision.
Carte 399
Question
If results match a prediction once, what is the safest conclusion?
Réponse
The results support the hypothesis under those conditions. One result does not prove the hypothesis in every setting.
Carte 400
Question
What is a direct relationship between two variables?
Réponse
As one increases, the other tends to increase; as one decreases, the other tends to decrease. The relationship need not be perfectly linear.
Carte 401
Question
Which variable is usually placed on the x-axis of an experimental graph?
Réponse
The independent variable. It is the factor selected or changed by the investigator.
Carte 402
Question
What does the slope of a straight-line graph represent?
Réponse
Change in y divided by change in x. It is the response rate per unit change in the other variable.
Carte 403
Question
A line rises 12 units in y while x rises 3 units. What is its slope?
Réponse
4 units of y per unit of x. Divide 12 by 3.
Carte 404
Question
What is an inverse relationship?
Réponse
As one variable increases, the other tends to decrease. Their product is constant only in a strictly inverse proportion.
Carte 405
Question
Which variable is usually placed on the y-axis of an experimental graph?
Réponse
The dependent variable. It is the measured response.
Carte 406
Question
What does a plateau on a response graph indicate?
Réponse
The measured response has stopped changing much despite further x increases. A limiting factor may have been reached.
Carte 407
Question
What is interpolation?
Réponse
Estimating a value within the range of measured data. It is generally safer than extrapolating beyond that range.
Carte 408
Question
What pattern suggests no relationship between two plotted variables?
Réponse
The response shows no consistent change as the other variable changes. Points may scatter without a trend.
Carte 409
Question
Before comparing values in a data table, what should you check?
Réponse
Headings, units, and conditions. Numbers from different measures or scales cannot be compared directly.
Carte 410
Question
If 3 samples require 12 mL total, how much is needed for 5 equal samples?
Réponse
20 mL. The rate is 4 mL per sample, so multiply by 5.
Carte 411
Question
How is the arithmetic mean calculated?
Réponse
Add all values and divide by the number of values. A large outlier can shift the mean.
Carte 412
Question
Why is extrapolation uncertain?
Réponse
It assumes the observed trend continues outside measured conditions. The relationship may change beyond the data range.
Carte 413
Question
A culture grows from 20 to 50 cells in 6 hours. What is the average growth rate?
Réponse
5 cells per hour. The change is 30 cells divided by 6 hours.
Carte 414
Question
A measurement rises from 40 to 50. What is the percent increase?
Réponse
25%. The increase is 10, and 10 ÷ 40 × 100 = 25%.
Carte 415
Question
When can the median describe a typical value better than the mean?
Réponse
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.
Carte 416
Question
How do quantitative and qualitative data differ?
Réponse
Quantitative data are numerical; qualitative data describe categories or qualities. Both can answer scientific questions.
Carte 417
Question
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?
Réponse
6. The observed rate is 2 response units per dose unit, so interpolation at dose 3 gives 6.
Carte 418
Question
How can a graph reveal a nonlinear relationship?
Réponse
The points follow a curve rather than a straight line. The rate of change varies across the x-range.
Carte 419
Question
What is the range of a data set?
Réponse
Maximum minus minimum. It describes total spread but ignores the distribution between the endpoints.
Carte 420
Question
What makes a scientific research question testable?
Réponse
It identifies measurable variables or observable outcomes. The needed data must be obtainable.
Carte 421
Question
In an experiment, what is the independent variable?
Réponse
The factor deliberately changed or assigned by the investigator. In a simple one-factor experiment, changing one independent variable helps isolate its effect.
Carte 422
Question
What should a hypothesis connect?
Réponse
A proposed explanation with a measurable outcome. It should lead to a prediction that evidence can challenge.
Carte 423
Question
What is a controlled variable, or constant?
Réponse
A condition kept the same across groups. Holding it constant prevents it from explaining outcome differences.
Carte 424
Question
What is the purpose of a control group?
Réponse
It provides a comparison without the experimental treatment. Differences can then be attributed more confidently to the treatment.
Carte 425
Question
In an experiment, what is the dependent variable?
Réponse
The measured response. It may change because of the independent variable.
Carte 426
Question
What form can a useful experimental prediction take?
Réponse
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.
Carte 427
Question
What does a positive control demonstrate?
Réponse
That the setup can produce a known response. If it fails, the test system may be defective.
Carte 428
Question
Why randomly assign subjects to experimental groups?
Réponse
To distribute known and unknown differences more evenly. This reduces selection bias and confounding.
Carte 429
Question
How can blinding reduce bias?
Réponse
It keeps participants, observers, or both unaware of treatment assignments. Expectations are less likely to affect behavior or measurement.
Carte 430
Question
What is a placebo?
Réponse
An inactive treatment designed to resemble the experimental treatment. It helps separate treatment effects from expectation effects.
Carte 431
Question
What does a negative control demonstrate?
Réponse
What happens when the tested cause is absent. An unexpected response may reveal contamination or another source.
Carte 432
Question
Why does a larger sample often improve a study?
Réponse
It reduces the influence of chance variation and supports more stable estimates. It cannot repair a biased sampling method.
Carte 433
Question
Why repeat trials within an experiment?
Réponse
To estimate variability and check consistency. One unusual trial then has less influence.
Carte 434
Question
Why must an experimental procedure be detailed and standardized?
Réponse
So groups are treated consistently and others can reproduce the work. Uncontrolled procedural differences create alternative explanations.
Carte 435
Question
Why calibrate a measuring instrument before collecting data?
Réponse
To compare its readings with a known standard and reduce systematic error. Calibration improves confidence in accuracy.
Carte 436
Question
What is an operational definition?
Réponse
A precise statement of how a variable is measured or manipulated. It turns an abstract concept into a repeatable procedure.
Carte 437
Question
How does independent replication differ from repeated trials?
Réponse
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.
Carte 438
Question
Why should raw data be recorded before interpretation?
Réponse
It preserves the observations separately from conclusions. Others can check calculations and reasoning.
Carte 439
Question
What should a scientific conclusion do?
Réponse
Answer the research question using the data and acknowledge limits. It should not claim more than the design supports.
Carte 440
Question
What should happen when data do not support a hypothesis?
Réponse
Revise or reject the hypothesis and consider new tests. Data should not be altered to preserve the original idea.
Carte 441
Question
What is a study limitation?
Réponse
A feature that restricts interpretation or generalization. Small samples, short duration, and imperfect measurements are examples.
Carte 442
Question
Why are ethics part of experimental design?
Réponse
Research must protect participants, organisms, and communities while balancing risks and benefits. Consent and humane treatment are key examples.
Carte 443
Question
How does an observational study differ from an experiment?
Réponse
It measures variables without assigning the exposure. It can find associations but usually supports weaker causal conclusions.
Carte 444
Question
Plants receive 0, 2, or 4 hours of added light, and growth is measured. What is the independent variable?
Réponse
Hours of added light. Plant growth is the dependent variable.
Carte 445
Question
A fertilizer study gives every plant the same water, soil, and temperature. What are these conditions?
Réponse
Controlled variables. Keeping them constant isolates the fertilizer's effect.
Carte 446
Question
A drug group improves more than a control group, but the groups were not randomly assigned. What is the main caution?
Réponse
Preexisting group differences could explain some improvement. The result is suggestive, but the design weakens a causal claim.

Illustrated anatomy torso surrounded by a cell, DNA helix, molecule, flask, and data plot on a dark blue background.

446 cartes