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.

Per Flashcards Open Source App

Sobre aquesta baralla

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.

Targetes d'aquesta baralla

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