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