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.

Om denne bunke

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.

Kort i denne bunke

  1. Kort 1

    Spørgsmål

    What posture defines the standard anatomical position?

    Svar

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

  2. Kort 2

    Spørgsmål

    In anatomical language, what does superior mean?

    Svar

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

  3. Kort 3

    Spørgsmål

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

    Svar

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

  4. Kort 4

    Spørgsmål

    Why does the body use feedback mechanisms?

    Svar

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

  5. Kort 5

    Spørgsmål

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

    Svar

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

  6. Kort 6

    Spørgsmål

    What does anterior mean in human anatomy?

    Svar

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

  7. Kort 7

    Spørgsmål

    Which plane divides the body into upper and lower portions?

    Svar

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

  8. Kort 8

    Spørgsmål

    What is homeostasis?

    Svar

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

  9. Kort 9

    Spørgsmål

    Which major body cavity contains the brain and spinal cord?

    Svar

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

  10. Kort 10

    Spørgsmål

    What does medial mean in anatomical language?

    Svar

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

  11. Kort 11

    Spørgsmål

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

    Svar

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

  12. Kort 12

    Spørgsmål

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

    Svar

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

  13. Kort 13

    Spørgsmål

    Which major body cavity contains the thoracic and abdominopelvic cavities?

    Svar

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

  14. Kort 14

    Spørgsmål

    What does proximal mean when describing a limb?

    Svar

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

  15. Kort 15

    Spørgsmål

    How does positive feedback differ from negative feedback?

    Svar

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

  16. Kort 16

    Spørgsmål

    Which tissue type covers surfaces and lines body cavities?

    Svar

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

  17. Kort 17

    Spørgsmål

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

    Svar

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

  18. Kort 18

    Spørgsmål

    What shared property lets muscle tissue produce movement?

    Svar

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

  19. Kort 19

    Spørgsmål

    Which tissue type rapidly communicates by electrical signals?

    Svar

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

  20. Kort 20

    Spørgsmål

    Why are tightly packed epithelial cells well suited for barriers?

    Svar

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

  21. Kort 21

    Spørgsmål

    What distinguishes connective tissue from epithelial tissue?

    Svar

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

  22. Kort 22

    Spørgsmål

    What are the four basic human tissue types?

    Svar

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

  23. Kort 23

    Spørgsmål

    What makes a structure an organ rather than a tissue?

    Svar

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

  24. Kort 24

    Spørgsmål

    What are the skeletal system's main functions?

    Svar

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

  25. Kort 25

    Spørgsmål

    What belongs to the axial skeleton?

    Svar

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

  26. Kort 26

    Spørgsmål

    How do compact and spongy bone differ?

    Svar

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

  27. Kort 27

    Spørgsmål

    What is a joint?

    Svar

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

  28. Kort 28

    Spørgsmål

    Which bone cell builds new bone matrix?

    Svar

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

  29. Kort 29

    Spørgsmål

    What belongs to the appendicular skeleton?

    Svar

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

  30. Kort 30

    Spørgsmål

    What is the main role of red bone marrow?

    Svar

    Blood-cell production. This process is called hematopoiesis.

  31. Kort 31

    Spørgsmål

    Which joint class allows the greatest range of motion?

    Svar

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

  32. Kort 32

    Spørgsmål

    Which bone cell breaks down bone matrix?

    Svar

    An osteoclast. Bone resorption helps remodeling and mineral balance.

  33. Kort 33

    Spørgsmål

    What does a ligament connect?

    Svar

    Bone to bone. A tendon connects muscle to bone.

  34. Kort 34

    Spørgsmål

    What is the shaft of a long bone called?

    Svar

    The diaphysis. The enlarged ends are the epiphyses.

  35. Kort 35

    Spørgsmål

    Why is bone important to blood-calcium balance?

    Svar

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

  36. Kort 36

    Spørgsmål

    What is stored mainly in yellow bone marrow?

    Svar

    Fat. It serves as an energy reserve.

  37. Kort 37

    Spørgsmål

    What does articular cartilage do at a synovial joint?

    Svar

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

  38. Kort 38

    Spørgsmål

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

    Svar

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

  39. Kort 39

    Spørgsmål

    What is bone remodeling?

    Svar

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

  40. Kort 40

    Spørgsmål

    Which muscle tissue is usually under voluntary control?

    Svar

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

  41. Kort 41

    Spørgsmål

    What is a sarcomere?

    Svar

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

  42. Kort 42

    Spørgsmål

    What does a tendon connect?

    Svar

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

  43. Kort 43

    Spørgsmål

    Which proteins slide past one another during muscle contraction?

    Svar

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

  44. Kort 44

    Spørgsmål

    Where is smooth muscle commonly found?

    Svar

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

  45. Kort 45

    Spørgsmål

    What ion exposes binding sites needed for skeletal muscle contraction?

    Svar

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

  46. Kort 46

    Spørgsmål

    How do antagonistic muscle pairs move a joint?

    Svar

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

  47. Kort 47

    Spørgsmål

    Why does muscle contraction require ATP?

    Svar

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

  48. Kort 48

    Spørgsmål

    Which muscle tissue makes up the heart wall?

    Svar

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

  49. Kort 49

    Spørgsmål

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

    Svar

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

  50. Kort 50

    Spørgsmål

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

    Svar

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

  51. Kort 51

    Spørgsmål

    What is muscle tone?

    Svar

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

  52. Kort 52

    Spørgsmål

    How does skeletal muscle help regulate body temperature?

    Svar

    Contraction releases heat. Shivering increases rapid contractions when the body is cold.

  53. Kort 53

    Spørgsmål

    What are the three muscle tissue types?

    Svar

    Skeletal, cardiac, and smooth muscle. They differ in location, structure, and control.

  54. Kort 54

    Spørgsmål

    What is a neuron's main function?

    Svar

    To receive, process, and transmit information. Neurons use electrical signals and chemical messengers.

  55. Kort 55

    Spørgsmål

    What structures make up the central nervous system?

    Svar

    The brain and spinal cord. They integrate information and coordinate responses.

  56. Kort 56

    Spørgsmål

    Which part of a neuron usually receives incoming signals?

    Svar

    The dendrites. The cell body integrates much of that input.

  57. Kort 57

    Spørgsmål

    What does the peripheral nervous system include?

    Svar

    Nerves and ganglia outside the brain and spinal cord. It links the central nervous system with the rest of the body.

  58. Kort 58

    Spørgsmål

    Which neuron structure carries an impulse away from the cell body?

    Svar

    The axon. Its terminals communicate with another cell.

  59. Kort 59

    Spørgsmål

    Which nervous-system division controls skeletal muscles voluntarily?

    Svar

    The somatic nervous system. It also carries sensory information from skin, muscles, and joints.

  60. Kort 60

    Spørgsmål

    What is a synapse?

    Svar

    A junction where one neuron communicates with another cell. Chemical synapses use neurotransmitters across a small gap.

  61. Kort 61

    Spørgsmål

    Which nervous-system division regulates organs and glands without conscious control?

    Svar

    The autonomic nervous system. It includes sympathetic and parasympathetic divisions.

  62. Kort 62

    Spørgsmål

    How does myelin affect nerve signaling?

    Svar

    It speeds impulse conduction along an axon. Myelin insulates segments of the axon.

  63. Kort 63

    Spørgsmål

    Which autonomic division prepares the body for acute activity?

    Svar

    The sympathetic division. It generally increases alertness and supports a fight-or-flight response.

  64. Kort 64

    Spørgsmål

    What is a reflex?

    Svar

    A rapid, predictable response to a stimulus. A reflex pathway can act before conscious awareness.

  65. Kort 65

    Spørgsmål

    Which autonomic division supports rest, digestion, and energy conservation?

    Svar

    The parasympathetic division. It generally promotes routine maintenance functions.

  66. Kort 66

    Spørgsmål

    Which brain region is most associated with conscious thought and voluntary movement?

    Svar

    The cerebrum. Its cortex also processes much sensory information.

  67. Kort 67

    Spørgsmål

    Which brain region fine-tunes balance and coordinated movement?

    Svar

    The cerebellum. It compares intended movement with sensory feedback.

  68. Kort 68

    Spørgsmål

    Which brain region controls vital automatic functions such as breathing and heart rate?

    Svar

    The brainstem. It also connects higher brain regions with the spinal cord.

  69. Kort 69

    Spørgsmål

    How do sensory and motor neurons differ?

    Svar

    Sensory neurons carry information toward the CNS; motor neurons carry commands away. Interneurons connect and process signals within the CNS.

  70. Kort 70

    Spørgsmål

    What does a sensory receptor do?

    Svar

    It converts a stimulus into a neural signal. Different receptors respond best to particular forms of energy or chemicals.

  71. Kort 71

    Spørgsmål

    What is a hormone?

    Svar

    A chemical messenger released into body fluids to affect target cells. A target responds only if it has the appropriate receptor.

  72. Kort 72

    Spørgsmål

    Why is the pituitary gland often called a master gland?

    Svar

    Several pituitary hormones regulate other endocrine glands. The hypothalamus controls much of pituitary activity.

  73. Kort 73

    Spørgsmål

    Why can one hormone affect some cells but not others?

    Svar

    Only target cells have the matching receptor. Receptor binding starts the cell's response.

  74. Kort 74

    Spørgsmål

    Which gland produces hormones that broadly increase metabolic activity?

    Svar

    The thyroid gland. Thyroid hormones influence energy use and development.

  75. Kort 75

    Spørgsmål

    What is insulin's main effect on blood glucose?

    Svar

    It lowers blood glucose. Insulin promotes glucose uptake and storage after a meal.

  76. Kort 76

    Spørgsmål

    Which glands release a hormone that raises blood calcium?

    Svar

    The parathyroid glands. Parathyroid hormone acts on bone, kidneys, and vitamin D pathways.

  77. Kort 77

    Spørgsmål

    Which adrenal region releases epinephrine during acute stress?

    Svar

    The adrenal medulla. Its hormones reinforce sympathetic nervous-system effects.

  78. Kort 78

    Spørgsmål

    Which organ has both endocrine and digestive functions?

    Svar

    The pancreas. Its islets release hormones, while other cells release digestive enzymes.

  79. Kort 79

    Spørgsmål

    What is glucagon's main effect on blood glucose?

    Svar

    It raises blood glucose. It promotes release of stored glucose during fasting.

  80. Kort 80

    Spørgsmål

    Rising thyroid hormone reduces its own upstream stimulation. What pattern is this?

    Svar

    Negative feedback. The final hormone limits further release along the control pathway.

  81. Kort 81

    Spørgsmål

    Which adrenal region produces steroid hormones such as cortisol and aldosterone?

    Svar

    The adrenal cortex. It surrounds the adrenal medulla.

  82. Kort 82

    Spørgsmål

    Which gland releases melatonin and helps regulate daily sleep timing?

    Svar

    The pineal gland. Light information influences its secretion pattern.

  83. Kort 83

    Spørgsmål

    Which hormone directly increases collecting-duct water permeability?

    Svar

    Antidiuretic hormone, or ADH. It makes collecting ducts more permeable to water, increasing water reabsorption and usually producing less, more concentrated urine.

  84. Kort 84

    Spørgsmål

    Which hormone strengthens uterine contractions during labor?

    Svar

    Oxytocin. This is a classic positive-feedback pathway that ends after delivery.

  85. Kort 85

    Spørgsmål

    How does endocrine signaling generally differ from nervous signaling?

    Svar

    It is usually slower to start and longer lasting. Hormones travel through body fluids, while neurons signal specific targets rapidly.

  86. Kort 86

    Spørgsmål

    What is plasma?

    Svar

    The liquid portion of blood. It carries cells, nutrients, hormones, proteins, wastes, and dissolved gases.

  87. Kort 87

    Spørgsmål

    Which side of the heart pumps blood to the lungs?

    Svar

    The right side. The right ventricle sends deoxygenated blood through the pulmonary trunk and arteries.

  88. Kort 88

    Spørgsmål

    What is the main function of red blood cells?

    Svar

    Transporting oxygen. Their hemoglobin also carries a smaller share of carbon dioxide.

  89. Kort 89

    Spørgsmål

    What defines an artery?

    Svar

    It carries blood away from the heart. Oxygen content does not define it; pulmonary arteries carry deoxygenated blood.

  90. Kort 90

    Spørgsmål

    What is the main function of white blood cells?

    Svar

    Body defense. Different white blood cells recognize, attack, or coordinate responses to threats.

  91. Kort 91

    Spørgsmål

    Which side of the heart pumps blood into systemic circulation?

    Svar

    The left side. The left ventricle sends oxygenated blood into the aorta.

  92. Kort 92

    Spørgsmål

    What is the main purpose of heart valves?

    Svar

    To keep blood moving in one direction. Pressure differences open and close them.

  93. Kort 93

    Spørgsmål

    What defines a vein?

    Svar

    It carries blood toward the heart. Many veins contain valves that limit backflow.

  94. Kort 94

    Spørgsmål

    What is the main role of platelets?

    Svar

    Helping stop bleeding. They form a platelet plug and support clotting reactions at a damaged vessel.

  95. Kort 95

    Spørgsmål

    Why are capillaries well suited for exchange?

    Svar

    Their walls are only one cell layer thick. Their small diameter and large total surface area support diffusion and filtration.

  96. Kort 96

    Spørgsmål

    After blood enters the right atrium, what chamber receives it next?

    Svar

    The right ventricle. Blood passes through the tricuspid valve before entering that chamber.

  97. Kort 97

    Spørgsmål

    What happens during ventricular systole?

    Svar

    The ventricles contract and eject blood. The right ventricle pumps to the lungs, and the left pumps to the body.

  98. Kort 98

    Spørgsmål

    What is pulmonary circulation?

    Svar

    Blood flow between the heart and lungs. It allows gas exchange and returns oxygenated blood to the left atrium.

  99. Kort 99

    Spørgsmål

    What normally sets the heart's rhythm?

    Svar

    The sinoatrial, or SA, node. Its spontaneous electrical activity initiates each heartbeat.

  100. Kort 100

    Spørgsmål

    What molecule in red blood cells binds oxygen?

    Svar

    Hemoglobin. Its iron-containing heme groups bind oxygen reversibly.

  101. Kort 101

    Spørgsmål

    What happens during ventricular diastole?

    Svar

    The ventricles relax and fill. Atrioventricular valves are open during most ventricular filling.

  102. Kort 102

    Spørgsmål

    What is systemic circulation?

    Svar

    Blood flow between the heart and the body's tissues. It delivers oxygen and nutrients and returns wastes.

  103. Kort 103

    Spørgsmål

    What does arterial blood pressure measure?

    Svar

    The force of blood against artery walls. It is commonly reported as systolic over diastolic pressure.

  104. Kort 104

    Spørgsmål

    What do coronary arteries supply?

    Svar

    The heart muscle itself. Blocked coronary blood flow can deprive myocardium of oxygen.

  105. Kort 105

    Spørgsmål

    Which major vessels return systemic blood to the right atrium?

    Svar

    The superior and inferior venae cavae. The superior vessel drains the upper body; the inferior drains the lower body.

  106. Kort 106

    Spørgsmål

    What is the respiratory system's primary gas-exchange function?

    Svar

    Bringing oxygen into the body and removing carbon dioxide. Ventilation moves air, while diffusion exchanges gases.

  107. Kort 107

    Spørgsmål

    What is the airflow sequence from the pharynx to the gas-exchange surfaces?

    Svar

    Pharynx, larynx, trachea, bronchi, bronchioles, alveoli. Each branch conducts air deeper into the lungs.

  108. Kort 108

    Spørgsmål

    Where does most gas exchange occur in the lungs?

    Svar

    Across the alveolar-capillary membrane. Thin walls and a large surface area shorten diffusion distance.

  109. Kort 109

    Spørgsmål

    What does the diaphragm do during quiet inhalation?

    Svar

    It contracts and moves downward. Thoracic volume rises, lung pressure falls, and air flows inward.

  110. Kort 110

    Spørgsmål

    Why does oxygen move from alveoli into pulmonary capillaries?

    Svar

    Its partial pressure is higher in alveolar air than in incoming blood. Oxygen diffuses down that gradient.

  111. Kort 111

    Spørgsmål

    What drives quiet exhalation?

    Svar

    Elastic recoil after inspiratory muscles relax. Thoracic volume falls and pressure pushes air outward.

  112. Kort 112

    Spørgsmål

    What is the pleura?

    Svar

    A double membrane surrounding each lung. A thin fluid layer reduces friction during breathing.

  113. Kort 113

    Spørgsmål

    How is most oxygen transported in blood?

    Svar

    Bound to hemoglobin in red blood cells. Only a small amount dissolves directly in plasma.

  114. Kort 114

    Spørgsmål

    Why does carbon dioxide move from pulmonary blood into alveoli?

    Svar

    Its partial pressure is higher in incoming blood than in alveolar air. It diffuses down that gradient for exhalation.

  115. Kort 115

    Spørgsmål

    What helps keep swallowed material out of the airway?

    Svar

    The epiglottis and coordinated swallowing reflexes. The laryngeal opening is protected as food passes.

  116. Kort 116

    Spørgsmål

    How does the conducting airway remove trapped particles?

    Svar

    Mucus traps them, and cilia move the mucus toward the throat. This is the mucociliary escalator.

  117. Kort 117

    Spørgsmål

    In what form is most carbon dioxide transported in blood?

    Svar

    As bicarbonate ions. Red blood cells help convert carbon dioxide and water into bicarbonate.

  118. Kort 118

    Spørgsmål

    Which blood change is a strong normal stimulus to increase breathing?

    Svar

    A rise in carbon dioxide and the associated fall in pH. Brainstem centers adjust ventilation in response.

  119. Kort 119

    Spørgsmål

    Why must alveoli receive both air and blood?

    Svar

    Gas exchange needs ventilation and perfusion. Air without blood flow, or blood without airflow, cannot exchange gases effectively.

  120. Kort 120

    Spørgsmål

    Why does ventilation increase during exercise?

    Svar

    Active tissues use more oxygen and produce more carbon dioxide. Faster, deeper breathing helps meet that demand.

  121. Kort 121

    Spørgsmål

    What are the digestive system's core functions?

    Svar

    Ingestion, digestion, absorption, and elimination. Movement and secretion support those processes.

  122. Kort 122

    Spørgsmål

    What is the alimentary-canal sequence after the mouth?

    Svar

    Pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus. Food passes through this continuous tube.

  123. Kort 123

    Spørgsmål

    What is mechanical digestion?

    Svar

    Physical breakdown and mixing of food without changing its molecules. Chewing and stomach churning are examples.

  124. Kort 124

    Spørgsmål

    What are two major functions of the stomach?

    Svar

    It stores and mixes food and begins substantial protein digestion. Acid denatures proteins, converts pepsinogen to pepsin, and provides the low pH pepsin needs.

  125. Kort 125

    Spørgsmål

    Where does most nutrient absorption occur?

    Svar

    The small intestine. Folds, villi, and microvilli create a large absorptive surface.

  126. Kort 126

    Spørgsmål

    Which nutrient does salivary amylase begin digesting in the mouth?

    Svar

    Carbohydrates, especially starch. Salivary amylase breaks starch into smaller carbohydrates.

  127. Kort 127

    Spørgsmål

    What is chemical digestion?

    Svar

    Enzymatic breakdown of large food molecules into absorbable units. Chemical bonds are changed during the process.

  128. Kort 128

    Spørgsmål

    What is peristalsis?

    Svar

    Wave-like smooth-muscle contractions that move material forward. It occurs throughout much of the digestive tract.

  129. Kort 129

    Spørgsmål

    What is a main function of the large intestine?

    Svar

    Absorbing water and electrolytes and forming feces. Resident microbes also process some undigested material.

  130. Kort 130

    Spørgsmål

    What digestive product does the liver make?

    Svar

    Bile. Bile salts help disperse dietary fat into smaller droplets.

  131. Kort 131

    Spørgsmål

    What does a digestive sphincter do?

    Svar

    It regulates movement between regions of the digestive tract. Circular muscle contracts to close a passage.

  132. Kort 132

    Spørgsmål

    What does the pancreas release into the small intestine?

    Svar

    Digestive enzymes and bicarbonate-rich fluid. Bicarbonate helps neutralize acidic material from the stomach.

  133. Kort 133

    Spørgsmål

    How do intestinal villi improve absorption?

    Svar

    They increase surface area. Each villus contains blood capillaries and a lymphatic lacteal for transported nutrients.

  134. Kort 134

    Spørgsmål

    What is the gallbladder's role?

    Svar

    It stores and concentrates bile. It releases bile into the small intestine when fatty food arrives.

  135. Kort 135

    Spørgsmål

    Which macronutrient's absorbed products usually enter intestinal lacteals before reaching the blood?

    Svar

    Most dietary lipids. Their absorbed products travel through lymph before entering the bloodstream.

  136. Kort 136

    Spørgsmål

    Which accessory organs help digestion without food passing through them?

    Svar

    The teeth, tongue, salivary glands, liver, gallbladder, and pancreas. Teeth and the tongue act mechanically; the other accessory organs add or store digestive secretions.

  137. Kort 137

    Spørgsmål

    What organs make up the urinary system?

    Svar

    The kidneys, ureters, urinary bladder, and urethra. Kidneys make urine; the remaining organs transport, store, and release it.

  138. Kort 138

    Spørgsmål

    What is a nephron?

    Svar

    The kidney's functional unit. It filters blood and adjusts the filtrate to form urine.

  139. Kort 139

    Spørgsmål

    Where does blood filtration begin in a nephron?

    Svar

    At the renal corpuscle. Pressure pushes water and small solutes from glomerular capillaries into the capsule.

  140. Kort 140

    Spørgsmål

    What moves urine from a kidney to the bladder?

    Svar

    A ureter. Smooth-muscle contractions propel urine along the tube.

  141. Kort 141

    Spørgsmål

    What is the urinary bladder's main role?

    Svar

    Temporary urine storage. Stretch receptors help trigger the urge to urinate as it fills.

  142. Kort 142

    Spørgsmål

    Which structure carries urine from the bladder out of the body?

    Svar

    The urethra. It is distinct from the ureters that enter the bladder.

  143. Kort 143

    Spørgsmål

    What is tubular reabsorption?

    Svar

    Movement of useful substances from nephron fluid back into blood. Water, glucose, and ions are common examples.

  144. Kort 144

    Spørgsmål

    What is the glomerulus?

    Svar

    A capillary tuft that filters blood in the renal corpuscle. Cells and most large proteins normally remain in circulation.

  145. Kort 145

    Spørgsmål

    How does more ADH change urine?

    Svar

    It makes urine more concentrated and lowers its volume. More water is reabsorbed from the collecting ducts.

  146. Kort 146

    Spørgsmål

    What path does filtrate follow after entering the glomerular capsule?

    Svar

    Proximal convoluted tubule → nephron loop → distal convoluted tubule → collecting duct. The collecting duct receives forming urine from multiple nephrons.

  147. Kort 147

    Spørgsmål

    What is tubular secretion?

    Svar

    Movement of selected substances from blood into nephron fluid. It helps eliminate wastes and regulate ions and pH.

  148. Kort 148

    Spørgsmål

    Besides removing waste, what does the urinary system regulate?

    Svar

    Water, electrolytes, acid-base balance, and blood volume. Kidney hormones also affect blood pressure and red-cell production.

  149. Kort 149

    Spørgsmål

    Why does dehydration usually reduce urine volume?

    Svar

    The body conserves water by increasing renal reabsorption. ADH is an important signal in this response.

  150. Kort 150

    Spørgsmål

    Why do the kidneys receive a large blood flow?

    Svar

    They must continuously filter plasma and regulate its composition. High flow supports waste removal and homeostasis.

  151. Kort 151

    Spørgsmål

    What is lymph?

    Svar

    Interstitial fluid that has entered lymphatic vessels. It eventually returns to the bloodstream.

  152. Kort 152

    Spørgsmål

    What is innate immunity?

    Svar

    Rapid, nonspecific defense present before a particular exposure. Barriers, inflammation, and several immune cells contribute.

  153. Kort 153

    Spørgsmål

    What is a major function of lymph nodes?

    Svar

    Filtering lymph and providing sites for immune-cell activation. Swelling can reflect an active immune response.

  154. Kort 154

    Spørgsmål

    What does the spleen filter?

    Svar

    Blood. It removes aged blood cells and supports immune responses to blood-borne antigens.

  155. Kort 155

    Spørgsmål

    What is a key function of B lymphocytes?

    Svar

    Producing antibody-secreting cells and memory cells. Antibodies bind specific antigens.

  156. Kort 156

    Spørgsmål

    What distinguishes adaptive immunity?

    Svar

    It targets specific antigens and develops memory. Later exposure can trigger a faster, stronger response.

  157. Kort 157

    Spørgsmål

    Which lymphatic organ is important for T-cell maturation?

    Svar

    The thymus. It is most active early in life.

  158. Kort 158

    Spørgsmål

    What is the body's first physical barrier against many pathogens?

    Svar

    Intact skin and mucous membranes. Their secretions and normal microbes add protection.

  159. Kort 159

    Spørgsmål

    What is a key function of T lymphocytes?

    Svar

    Coordinating immune responses or killing infected cells. Different T-cell types perform different roles.

  160. Kort 160

    Spørgsmål

    What does an antibody bind?

    Svar

    A specific antigen. Binding can neutralize a target or mark it for other immune defenses.

  161. Kort 161

    Spørgsmål

    What is the purpose of inflammation after tissue injury?

    Svar

    To contain damage, recruit defenses, and begin repair. Redness, heat, swelling, and pain can accompany it.

  162. Kort 162

    Spørgsmål

    Why is a second adaptive response often faster than the first?

    Svar

    Memory lymphocytes remain after the first exposure. They respond quickly when the same antigen appears again.

  163. Kort 163

    Spørgsmål

    What does a phagocyte do?

    Svar

    It engulfs particles, microbes, or debris. Neutrophils and macrophages are important examples.

  164. Kort 164

    Spørgsmål

    How does vaccination support adaptive immunity?

    Svar

    It safely exposes the immune system to antigen information. This promotes memory without requiring the full disease.

  165. Kort 165

    Spørgsmål

    Why is lymphatic fluid return important?

    Svar

    It prevents excess interstitial fluid from accumulating. Lymphatic vessels return fluid and leaked proteins to blood.

  166. Kort 166

    Spørgsmål

    What structures belong to the integumentary system?

    Svar

    Skin, hair, nails, sweat glands, and sebaceous glands. Together they form the body's outer covering.

  167. Kort 167

    Spørgsmål

    What is the epidermis?

    Svar

    The outer epithelial layer of skin. It is avascular and contains protective keratinized cells.

  168. Kort 168

    Spørgsmål

    How does sweating cool the body?

    Svar

    Evaporation removes heat from the skin. Skin blood-flow changes also help regulate heat loss.

  169. Kort 169

    Spørgsmål

    What is a major role of melanin in skin?

    Svar

    Absorbing some ultraviolet radiation. It also contributes to skin and hair color.

  170. Kort 170

    Spørgsmål

    How does skin contribute to sensation?

    Svar

    Sensory receptors detect touch, pressure, pain, and temperature. Nerves carry that information to the CNS.

  171. Kort 171

    Spørgsmål

    What is the dermis?

    Svar

    The connective-tissue layer beneath the epidermis. It contains vessels, nerves, glands, and hair follicles.

  172. Kort 172

    Spørgsmål

    How does skin support vitamin D production?

    Svar

    Ultraviolet light starts conversion of a skin molecule into a vitamin D precursor. The liver and kidneys complete activation.

  173. Kort 173

    Spørgsmål

    Why does a deep skin wound bleed but a shallow epidermal scrape may not?

    Svar

    Blood vessels are in the dermis, not the epidermis. A wound must reach vascular tissue to damage them.

  174. Kort 174

    Spørgsmål

    What is a gamete?

    Svar

    A haploid reproductive cell. Human sperm and oocytes each carry 23 chromosomes.

  175. Kort 175

    Spørgsmål

    What are the testes' two main reproductive functions?

    Svar

    Producing sperm and secreting testosterone. Sperm develop in seminiferous tubules.

  176. Kort 176

    Spørgsmål

    What tube carries sperm from the epididymis toward the ejaculatory duct?

    Svar

    The ductus, or vas, deferens. Smooth muscle propels sperm during ejaculation.

  177. Kort 177

    Spørgsmål

    What is ovulation?

    Svar

    Release of a secondary oocyte from an ovary. A surge in luteinizing hormone helps trigger it.

  178. Kort 178

    Spørgsmål

    Where does fertilization usually occur?

    Svar

    In a uterine tube. The early embryo then travels toward the uterus.

  179. Kort 179

    Spørgsmål

    What are the ovaries' two main reproductive functions?

    Svar

    Producing oocytes and secreting sex hormones. Estrogen and progesterone help regulate the reproductive cycle.

  180. Kort 180

    Spørgsmål

    What is the uterus' main reproductive role?

    Svar

    Supporting implantation and development of an embryo and fetus. Its muscular wall also contracts during birth.

  181. Kort 181

    Spørgsmål

    What causes menstruation when pregnancy does not occur?

    Svar

    Falling ovarian hormones allow the uterine lining to shed. A new cycle then begins.

  182. Kort 182

    Spørgsmål

    How does a sperm cell's structure support its function?

    Svar

    Its flagellum provides movement, and its head carries DNA plus enzymes used during fertilization. Mitochondria supply energy in the midpiece.

  183. Kort 183

    Spørgsmål

    What is the placenta's exchange role?

    Svar

    It allows gases, nutrients, and wastes to move between maternal and fetal circulations. Their blood normally does not mix directly.

  184. Kort 184

    Spørgsmål

    Why is meiosis necessary for sexual reproduction?

    Svar

    It halves chromosome number in gametes. Fertilization then restores the diploid number.

  185. Kort 185

    Spørgsmål

    How do sex hormones regulate reproductive control pathways?

    Svar

    They usually feed back on the hypothalamus and pituitary. This adjusts release of hormones that act on the gonads.

  186. Kort 186

    Spørgsmål

    What does cell theory state?

    Svar

    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.

  187. Kort 187

    Spørgsmål

    What is the defining structural feature of a prokaryotic cell?

    Svar

    It lacks a membrane-bound nucleus. Its DNA occupies a nucleoid region.

  188. Kort 188

    Spørgsmål

    What is the cell membrane's main role?

    Svar

    Regulating movement between the cell and its environment. Its phospholipid bilayer is selectively permeable.

  189. Kort 189

    Spørgsmål

    What is the nucleus' main role?

    Svar

    Storing most of a eukaryotic cell's DNA. Nuclear pores regulate exchange with the cytoplasm.

  190. Kort 190

    Spørgsmål

    Where are proteins assembled?

    Svar

    At ribosomes. Ribosomes may float in cytosol or attach to rough endoplasmic reticulum.

  191. Kort 191

    Spørgsmål

    What distinguishes a eukaryotic cell from a prokaryotic cell?

    Svar

    A eukaryotic cell has a membrane-bound nucleus and other membrane-bound organelles. Animals, plants, fungi, and protists are eukaryotes.

  192. Kort 192

    Spørgsmål

    What is a mitochondrion's main function?

    Svar

    Producing most cellular ATP through aerobic respiration. Its inner membrane provides a large reaction surface.

  193. Kort 193

    Spørgsmål

    What does rough endoplasmic reticulum mainly produce?

    Svar

    Proteins for secretion, membranes, or organelles. Ribosomes on its surface make the proteins.

  194. Kort 194

    Spørgsmål

    Which organelle carries out photosynthesis in plants and algae?

    Svar

    The chloroplast. It converts light energy into chemical energy stored in organic molecules.

  195. Kort 195

    Spørgsmål

    What does the Golgi apparatus do?

    Svar

    It modifies, sorts, and packages cell products. Vesicles carry those products to their destinations.

  196. Kort 196

    Spørgsmål

    What is a lysosome's role?

    Svar

    Digesting worn cell parts and engulfed material. Its enzymes work best in an acidic interior.

  197. Kort 197

    Spørgsmål

    What are major functions of smooth endoplasmic reticulum?

    Svar

    Lipid synthesis, detoxification, and calcium storage. Its membrane lacks attached ribosomes.

  198. Kort 198

    Spørgsmål

    What does the cytoskeleton provide?

    Svar

    Cell shape, internal organization, movement, and transport tracks. It is built from protein filaments.

  199. Kort 199

    Spørgsmål

    What is diffusion?

    Svar

    Net movement from higher to lower concentration. It is passive and continues until dynamic equilibrium is reached.

  200. Kort 200

    Spørgsmål

    What happens to an animal cell in a strongly hypotonic solution?

    Svar

    Water enters and the cell swells. Without a cell wall, it may burst.

  201. Kort 201

    Spørgsmål

    What happens during interphase?

    Svar

    The cell grows, performs normal functions, and copies its DNA. Interphase precedes mitotic division.

  202. Kort 202

    Spørgsmål

    What is the result of mitosis followed by cytokinesis?

    Svar

    Two genetically similar daughter cells. Chromosome number is normally preserved.

  203. Kort 203

    Spørgsmål

    What is osmosis?

    Svar

    Diffusion of water across a selectively permeable membrane. Water moves toward the side with more nonpenetrating solute.

  204. Kort 204

    Spørgsmål

    What happens to an animal cell in a hypertonic solution?

    Svar

    Water leaves and the cell shrinks. The external solution has a higher effective solute concentration.

  205. Kort 205

    Spørgsmål

    Why are cells generally small?

    Svar

    A high surface-area-to-volume ratio supports efficient exchange. Volume grows faster than surface area as a cell enlarges.

  206. Kort 206

    Spørgsmål

    What is cytokinesis?

    Svar

    Division of the cytoplasm. It separates one cell into two after nuclear division.

  207. Kort 207

    Spørgsmål

    How does active transport differ from passive transport?

    Svar

    It uses energy to move substances against a gradient. Passive transport moves down a gradient without direct energy input.

  208. Kort 208

    Spørgsmål

    What happens to an animal cell in an isotonic solution?

    Svar

    There is no net water movement. Water still crosses in both directions at equal rates.

  209. Kort 209

    Spørgsmål

    Which structures are typical of plant cells but not animal cells?

    Svar

    A cellulose cell wall, chloroplasts, and a large central vacuole. Both cell types have membranes, nuclei, and mitochondria.

  210. Kort 210

    Spørgsmål

    How do cells contribute to a multicellular organism's organization?

    Svar

    Specialized cells form tissues, tissues form organs, and organs form systems. Division of labor supports complex functions.

  211. Kort 211

    Spørgsmål

    What is DNA's primary biological role?

    Svar

    Storing hereditary information. Its nucleotide sequence contains instructions used to build functional RNA and proteins.

  212. Kort 212

    Spørgsmål

    What are the three parts of a DNA nucleotide?

    Svar

    A deoxyribose sugar, a phosphate group, and a nitrogenous base. Nucleotides link to form each strand.

  213. Kort 213

    Spørgsmål

    Which bases pair in double-stranded DNA?

    Svar

    Adenine with thymine, and cytosine with guanine. Hydrogen bonds hold complementary strands together.

  214. Kort 214

    Spørgsmål

    How does RNA differ from DNA?

    Svar

    RNA usually has ribose, uses uracil instead of thymine, and is usually single-stranded. Several RNA types help express genes.

  215. Kort 215

    Spørgsmål

    What is a gene?

    Svar

    A DNA sequence that contributes to a functional product. The product may be a protein or a functional RNA.

  216. Kort 216

    Spørgsmål

    What is a chromosome?

    Svar

    A long DNA molecule packaged with proteins. It contains many genes and other sequences.

  217. Kort 217

    Spørgsmål

    What is DNA replication?

    Svar

    Copying DNA before cell division. Each new DNA molecule contains one old strand and one newly made strand.

  218. Kort 218

    Spørgsmål

    What is the usual flow of information from a protein-coding gene?

    Svar

    DNA to RNA to protein. Transcription makes RNA; translation builds the polypeptide.

  219. Kort 219

    Spørgsmål

    What happens during transcription?

    Svar

    RNA is synthesized from a DNA template. For a protein-coding gene, that RNA functions as or is processed into messenger RNA.

  220. Kort 220

    Spørgsmål

    What does messenger RNA carry?

    Svar

    A copy of coding information from DNA to a ribosome. Its codons specify the amino-acid sequence.

  221. Kort 221

    Spørgsmål

    What is a codon?

    Svar

    A three-nucleotide sequence in mRNA. Most codons specify an amino acid; some signal start or stop.

  222. Kort 222

    Spørgsmål

    What is the usual role of the AUG codon?

    Svar

    It starts translation and specifies methionine. The ribosome uses it to establish the reading frame.

  223. Kort 223

    Spørgsmål

    What happens during translation?

    Svar

    A ribosome reads mRNA and joins amino acids into a polypeptide. Transfer RNAs match codons with amino acids.

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  224. Kort 224

    Spørgsmål

    What is transfer RNA's role in protein synthesis?

    Svar

    It carries an amino acid and matches its anticodon to an mRNA codon. This places the correct amino acid in sequence.

  225. Kort 225

    Spørgsmål

    What is an anticodon?

    Svar

    A three-base sequence on tRNA complementary to an mRNA codon. Pairing helps decode the message.

  226. Kort 226

    Spørgsmål

    What is a mutation?

    Svar

    A change in a DNA sequence. Its effect may be harmful, neutral, or beneficial depending on location and context.

  227. Kort 227

    Spørgsmål

    Why can a one-base insertion in a coding sequence have a large effect?

    Svar

    It can shift the reading frame. Every downstream codon may change until a stop signal appears.

  228. Kort 228

    Spørgsmål

    Why can changing one amino acid alter a protein's function?

    Svar

    Amino-acid sequence helps determine folding and shape. Shape controls many protein interactions.

  229. Kort 229

    Spørgsmål

    What is ribosomal RNA's role in protein synthesis?

    Svar

    It forms the structural and catalytic core of ribosomes. Ribosomal RNA helps align translation components and catalyzes peptide-bond formation.

  230. Kort 230

    Spørgsmål

    Why can different cell types contain the same DNA but perform different jobs?

    Svar

    They express different sets of genes. Different proteins give cells different structures and functions.

  231. Kort 231

    Spørgsmål

    Which mutation can be passed to offspring?

    Svar

    A mutation present in a gamete-forming lineage. A mutation limited to ordinary body cells is not inherited through reproduction.

  232. Kort 232

    Spørgsmål

    What is an allele?

    Svar

    An alternative version of a gene. Diploid individuals usually carry two alleles for each autosomal gene.

  233. Kort 233

    Spørgsmål

    What is genotype?

    Svar

    An organism's allele combination for a gene or set of genes. Genotype contributes to phenotype.

  234. Kort 234

    Spørgsmål

    What does homozygous mean?

    Svar

    Having two identical alleles for a gene. Examples include AA and aa.

  235. Kort 235

    Spørgsmål

    What makes an allele dominant in a simple Mendelian trait?

    Svar

    One copy is enough for its phenotype to appear in a heterozygote. Dominant does not mean common or beneficial.

  236. Kort 236

    Spørgsmål

    What does Mendel's law of segregation describe?

    Svar

    The two alleles for a gene separate during gamete formation. Each gamete receives one allele.

  237. Kort 237

    Spørgsmål

    What is phenotype?

    Svar

    An observable trait or characteristic. It can reflect genotype, environment, and their interaction.

  238. Kort 238

    Spørgsmål

    What does heterozygous mean?

    Svar

    Having two different alleles for a gene. An example is Aa.

  239. Kort 239

    Spørgsmål

    When does a recessive phenotype usually appear in a simple autosomal trait?

    Svar

    When both alleles are recessive. A heterozygote carries the allele without showing that phenotype.

  240. Kort 240

    Spørgsmål

    When does independent assortment apply most clearly?

    Svar

    When genes are on different chromosomes or far apart on the same chromosome. Their allele pairs enter gametes independently.

  241. Kort 241

    Spørgsmål

    What does a Punnett square predict?

    Svar

    Expected offspring genotype probabilities from specified parental gametes. It does not guarantee outcomes in a small family.

  242. Kort 242

    Spørgsmål

    For Aa × Aa, what is the chance of an aa offspring?

    Svar

    One fourth, or 25%. The genotype ratio is expected to be 1 AA : 2 Aa : 1 aa.

  243. Kort 243

    Spørgsmål

    For Aa × Aa with complete dominance, what phenotypic ratio is expected?

    Svar

    Three dominant-phenotype offspring to one recessive-phenotype offspring. This is a probability across many offspring.

  244. Kort 244

    Spørgsmål

    How can a test cross reveal the genotype behind a dominant phenotype?

    Svar

    Cross the individual with a homozygous recessive partner. Recessive offspring show that the unknown parent carried a recessive allele.

  245. Kort 245

    Spørgsmål

    What happens in incomplete dominance?

    Svar

    A heterozygote has an intermediate phenotype. Neither allele fully masks the other.

  246. Kort 246

    Spørgsmål

    How is the probability of two independent genetic events both occurring found?

    Svar

    Multiply their individual probabilities. This is the product rule.

  247. Kort 247

    Spørgsmål

    What does a pedigree show?

    Svar

    How a trait appears across generations of a family. Its pattern can suggest a mode of inheritance.

  248. Kort 248

    Spørgsmål

    Why can two parents have offspring ratios that differ from a Punnett-square expectation?

    Svar

    Each fertilization is a chance event. Expected ratios become more apparent with larger numbers of offspring.

  249. Kort 249

    Spørgsmål

    What happens in codominance?

    Svar

    Both alleles are distinctly expressed in a heterozygote. The AB blood type is a common example.

  250. Kort 250

    Spørgsmål

    What are major roles of carbohydrates?

    Svar

    Providing quick energy, storing energy, and forming some structures. Monosaccharides are their basic building blocks.

  251. Kort 251

    Spørgsmål

    What is a monomer?

    Svar

    A small building block that can join with others to form a larger molecule. Glucose, amino acids, and nucleotides are examples in different classes.

  252. Kort 252

    Spørgsmål

    What happens in a dehydration-synthesis reaction?

    Svar

    Monomers join while water is removed. The reaction builds a larger biological molecule.

  253. Kort 253

    Spørgsmål

    What does an enzyme do?

    Svar

    It lowers activation energy and speeds a reaction without being consumed. Its shape helps it bind specific substrates.

  254. Kort 254

    Spørgsmål

    What are major roles of lipids?

    Svar

    Long-term energy storage, membranes, insulation, and signaling. Lipids are mostly nonpolar and do not mix well with water.

  255. Kort 255

    Spørgsmål

    What does it mean for a protein to denature?

    Svar

    Its normal shape is disrupted. Heat, extreme pH, or chemicals can reduce its function.

  256. Kort 256

    Spørgsmål

    What happens during hydrolysis?

    Svar

    Water is used to split a larger molecule into smaller units. Digestion often uses hydrolysis reactions.

  257. Kort 257

    Spørgsmål

    Why do phospholipids form bilayers in water?

    Svar

    Their hydrophilic heads interact with water while hydrophobic tails turn inward. This arrangement forms cell-membrane structure.

  258. Kort 258

    Spørgsmål

    What are proteins built from?

    Svar

    Amino acids linked by peptide bonds. Their folded shapes support enzymes, transport, signaling, structure, and movement.

  259. Kort 259

    Spørgsmål

    How do starch and glycogen compare?

    Svar

    Both store glucose; plants use starch and animals use glycogen. Their branching patterns differ.

  260. Kort 260

    Spørgsmål

    How do saturated and unsaturated fatty acids differ?

    Svar

    Saturated fatty acids lack carbon-carbon double bonds; unsaturated ones have one or more. Double bonds often introduce bends.

  261. Kort 261

    Spørgsmål

    What immediate energy-carrying molecule powers many cell processes?

    Svar

    ATP. Energy released from nutrients can be transferred into ATP's phosphate bonds.

  262. Kort 262

    Spørgsmål

    What are nucleic acids built from?

    Svar

    Nucleotides. DNA stores hereditary information, while RNA performs several roles in gene expression.

  263. Kort 263

    Spørgsmål

    Which elements are common in all four major biological macromolecule classes?

    Svar

    Carbon, hydrogen, and oxygen. Nitrogen and phosphorus occur prominently in some classes.

  264. Kort 264

    Spørgsmål

    Why is three-dimensional shape important for macromolecules?

    Svar

    Shape determines many interactions and functions. A changed shape can prevent a molecule from binding its target.

  265. Kort 265

    Spørgsmål

    What are triglycerides built from?

    Svar

    One glycerol molecule and three fatty acids. They join through ester bonds to form a common energy-storage lipid.

  266. Kort 266

    Spørgsmål

    What is a pathogen?

    Svar

    An agent capable of causing disease. Not every microorganism is pathogenic.

  267. Kort 267

    Spørgsmål

    What type of cell is a bacterium?

    Svar

    A prokaryotic cell. Bacteria usually reproduce by binary fission.

  268. Kort 268

    Spørgsmål

    What cell type do fungi have?

    Svar

    Eukaryotic cells. Some fungi are unicellular yeasts, while others form multicellular filaments.

  269. Kort 269

    Spørgsmål

    What does disease transmission describe?

    Svar

    How an infectious agent moves to a susceptible host. Routes include contact, droplets, airborne spread, food, water, and vectors.

  270. Kort 270

    Spørgsmål

    What is a biological vector?

    Svar

    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.

  271. Kort 271

    Spørgsmål

    Why are viruses dependent on host cells?

    Svar

    They lack the complete machinery for reproduction and metabolism. They use host components to make new virus particles.

  272. Kort 272

    Spørgsmål

    What is a protist?

    Svar

    A diverse eukaryote that is not classified as an animal, plant, or fungus. Some protists cause disease, while many do not.

  273. Kort 273

    Spørgsmål

    Why do antibiotics not treat viral infections?

    Svar

    They target bacterial structures or processes that viruses lack. Antiviral drugs use different targets.

  274. Kort 274

    Spørgsmål

    How can normal microbiota protect a host?

    Svar

    They occupy space and use resources that pathogens might otherwise exploit. Some also support digestion or immune development.

  275. Kort 275

    Spørgsmål

    How does sterilization differ from disinfection?

    Svar

    Sterilization destroys or removes all microbial life, including resistant forms; disinfection reduces pathogens on objects. The required method depends on use.

  276. Kort 276

    Spørgsmål

    How do infection and disease differ?

    Svar

    Infection means an agent is established in a host; disease means normal function is impaired and signs or symptoms occur. Infection may be asymptomatic.

  277. Kort 277

    Spørgsmål

    How can breaking a transmission route reduce infectious disease?

    Svar

    It interrupts the chain connecting a source with a susceptible host. Hand hygiene, clean water, ventilation, and vector control target different links.

  278. Kort 278

    Spørgsmål

    What is an atom?

    Svar

    The smallest unit of an element that retains that element's chemical identity. Atoms contain a nucleus surrounded by electrons.

  279. Kort 279

    Spørgsmål

    What charge and location does an electron have?

    Svar

    Negative charge in the electron cloud around the nucleus. Electrons drive most chemical bonding.

  280. Kort 280

    Spørgsmål

    Why are valence electrons important?

    Svar

    They participate most directly in bonding and reactions. Their arrangement helps predict chemical behavior.

  281. Kort 281

    Spørgsmål

    What do elements in the same periodic-table group often share?

    Svar

    Similar valence-electron patterns and chemical properties. A group is a vertical column.

  282. Kort 282

    Spørgsmål

    What is an ion?

    Svar

    An atom or group of atoms with a net electric charge. Its total numbers of protons and electrons are unequal.

  283. Kort 283

    Spørgsmål

    What charge and location does a proton have?

    Svar

    Positive charge in the nucleus. The number of protons determines the element.

  284. Kort 284

    Spørgsmål

    What does an element's atomic number equal?

    Svar

    Its number of protons. A neutral atom has the same number of electrons.

  285. Kort 285

    Spørgsmål

    How does a neutral atom form a cation?

    Svar

    By losing one or more electrons. It has more protons than electrons and a positive charge.

  286. Kort 286

    Spørgsmål

    An atom has 8 protons. How many electrons does it have if it is neutral?

    Svar

    Eight electrons. Neutral atoms have equal positive and negative charges.

  287. Kort 287

    Spørgsmål

    What charge and location does a neutron have?

    Svar

    No electric charge, in the nucleus. Neutron number can vary among isotopes of an element.

  288. Kort 288

    Spørgsmål

    What does mass number equal?

    Svar

    Protons plus neutrons in one atom. It is a whole number for a specific isotope.

  289. Kort 289

    Spørgsmål

    How does a neutral atom form an anion?

    Svar

    By gaining one or more electrons. It has more electrons than protons and a negative charge.

  290. Kort 290

    Spørgsmål

    What does a period represent on the periodic table?

    Svar

    A horizontal row. Moving across a period changes proton number one element at a time.

  291. Kort 291

    Spørgsmål

    What are isotopes?

    Svar

    Atoms of the same element with different numbers of neutrons. They have the same atomic number but different mass numbers.

  292. Kort 292

    Spørgsmål

    What is matter?

    Svar

    Anything that has mass and occupies space. Solids, liquids, gases, and plasma are forms of matter.

  293. Kort 293

    Spørgsmål

    What distinguishes a solid from a liquid or gas?

    Svar

    A solid has a definite shape and volume. Its particles vibrate around relatively fixed positions.

  294. Kort 294

    Spørgsmål

    What is a physical change?

    Svar

    A change in form or state without changing chemical identity. Melting and cutting are examples.

  295. Kort 295

    Spørgsmål

    What is a physical property?

    Svar

    A characteristic observed without changing a substance's identity. Density, color, and melting point are examples.

  296. Kort 296

    Spørgsmål

    How does an element differ from a compound?

    Svar

    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.

  297. Kort 297

    Spørgsmål

    What distinguishes a liquid?

    Svar

    It has a definite volume but takes the shape of its container. Its particles remain close while moving past one another.

  298. Kort 298

    Spørgsmål

    What is a chemical change?

    Svar

    A process that forms one or more substances with new chemical identities. Bond rearrangement occurs.

  299. Kort 299

    Spørgsmål

    What is a chemical property?

    Svar

    A substance's ability to undergo a particular chemical change. Flammability and reactivity with acid are examples.

  300. Kort 300

    Spørgsmål

    Which phase changes connect solids and liquids?

    Svar

    Melting changes a solid to a liquid; freezing changes a liquid to a solid. These are opposite physical changes.

  301. Kort 301

    Spørgsmål

    How does a pure substance differ from a mixture?

    Svar

    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.

  302. Kort 302

    Spørgsmål

    What distinguishes a gas?

    Svar

    It has neither a definite shape nor a definite volume. It expands to fill its container.

  303. Kort 303

    Spørgsmål

    What is the formula for density?

    Svar

    Density = mass ÷ volume. Density is an intensive property.

  304. Kort 304

    Spørgsmål

    Which phase changes connect liquids and gases?

    Svar

    Vaporization changes a liquid to a gas; condensation changes a gas to a liquid. Evaporation is vaporization at a liquid's surface.

  305. Kort 305

    Spørgsmål

    What is a mixture?

    Svar

    Two or more substances physically combined in variable proportions. Its components retain their chemical identities.

  306. Kort 306

    Spørgsmål

    How do intensive and extensive properties differ?

    Svar

    Intensive properties do not depend on sample amount; extensive properties do. Density and temperature are intensive, while mass and volume are extensive.

  307. Kort 307

    Spørgsmål

    A 20 g sample occupies 5 mL. What is its density?

    Svar

    4 g/mL. Divide 20 g by 5 mL.

  308. Kort 308

    Spørgsmål

    Which phase changes connect solids and gases directly?

    Svar

    Sublimation changes a solid to a gas; deposition changes a gas to a solid. Neither transition passes through the liquid state.

  309. Kort 309

    Spørgsmål

    How do homogeneous and heterogeneous mixtures differ?

    Svar

    A homogeneous mixture is uniform throughout; a heterogeneous mixture is not. A solution is homogeneous.

  310. Kort 310

    Spørgsmål

    Where are reactants and products written in a chemical equation?

    Svar

    Reactants are on the left; products are on the right. The arrow shows the direction represented.

  311. Kort 311

    Spørgsmål

    Why must a chemical equation be balanced?

    Svar

    Atoms are conserved in ordinary chemical reactions. Each element must have the same atom count on both sides.

  312. Kort 312

    Spørgsmål

    What does a coefficient in a chemical equation change?

    Svar

    The number of whole particles or moles represented. It multiplies every atom in the following formula.

  313. Kort 313

    Spørgsmål

    Why should subscripts not be changed when balancing an equation?

    Svar

    Changing a subscript changes the substance's identity. Balancing changes coefficients only.

  314. Kort 314

    Spørgsmål

    What coefficients balance H₂ + O₂ → H₂O?

    Svar

    2, 1, 2: 2H₂ + O₂ → 2H₂O. Both sides then contain four hydrogen atoms and two oxygen atoms.

  315. Kort 315

    Spørgsmål

    What pattern defines a synthesis reaction?

    Svar

    Two or more reactants form a more complex product. A general pattern is A + B → AB.

  316. Kort 316

    Spørgsmål

    What are typical products when a hydrocarbon burns completely in oxygen?

    Svar

    Carbon dioxide and water. Incomplete combustion can produce carbon monoxide or carbon.

  317. Kort 317

    Spørgsmål

    What is the net ionic equation for a typical strong acid–strong base neutralization?

    Svar

    H⁺(aq) + OH⁻(aq) → H₂O(l). The remaining ions are spectators and do not appear in the net ionic equation.

  318. Kort 318

    Spørgsmål

    What is a precipitate?

    Svar

    An insoluble solid that forms from substances in solution. Its appearance can signal a chemical reaction.

  319. Kort 319

    Spørgsmål

    What pattern defines a decomposition reaction?

    Svar

    One compound breaks into simpler products. A general pattern is AB → A + B.

  320. Kort 320

    Spørgsmål

    What is an exothermic reaction?

    Svar

    A reaction that releases heat to the surroundings. The surroundings often warm.

  321. Kort 321

    Spørgsmål

    What occurs in an oxidation-reduction reaction?

    Svar

    Electrons transfer or atoms change oxidation state. Oxidation is electron loss; reduction is electron gain.

  322. Kort 322

    Spørgsmål

    What is activation energy?

    Svar

    The minimum energy barrier reactants must overcome to react. Catalysts lower this barrier.

  323. Kort 323

    Spørgsmål

    Which observations can provide evidence of a chemical reaction?

    Svar

    Gas formation, a precipitate, sustained color change, light, or temperature change. No single sign proves a reaction without context.

  324. Kort 324

    Spørgsmål

    What is an endothermic reaction?

    Svar

    A reaction that absorbs heat from the surroundings. The surroundings may cool.

  325. Kort 325

    Spørgsmål

    Why does raising temperature usually speed a reaction?

    Svar

    Particles collide more often and with greater energy. More collisions overcome activation energy.

  326. Kort 326

    Spørgsmål

    Why can higher reactant concentration increase reaction rate?

    Svar

    More reactant particles occupy a given volume. This raises collision frequency.

  327. Kort 327

    Spørgsmål

    Why does powdered solid often react faster than one large piece?

    Svar

    Powder exposes more surface area. More particles are available for collisions.

  328. Kort 328

    Spørgsmål

    How does a catalyst speed a reaction?

    Svar

    It provides a pathway with lower activation energy. The catalyst is regenerated rather than consumed overall.

  329. Kort 329

    Spørgsmål

    How can increasing pressure affect a reaction between gases?

    Svar

    It can increase rate by bringing gas particles closer together. Collision frequency rises when volume falls.

  330. Kort 330

    Spørgsmål

    What does a reaction inhibitor do?

    Svar

    It slows a reaction. It may block a pathway, interfere with a catalyst, or remove reactive intermediates.

  331. Kort 331

    Spørgsmål

    Why can very high temperature slow an enzyme-catalyzed reaction?

    Svar

    The enzyme can denature and lose its active shape. Moderate warming helps only within the enzyme's stable range.

  332. Kort 332

    Spørgsmål

    What is dynamic equilibrium?

    Svar

    Forward and reverse reactions continue at equal rates. Concentrations remain constant even though particles still react.

  333. Kort 333

    Spørgsmål

    Does a catalyst change the final equilibrium amounts?

    Svar

    No. It speeds forward and reverse reactions, so equilibrium is reached sooner without changing its position.

  334. Kort 334

    Spørgsmål

    At equilibrium, what usually happens when the concentration of a dissolved or gaseous reactant increases?

    Svar

    The system shifts toward consuming some added reactant. It forms more product until a new equilibrium is reached.

  335. Kort 335

    Spørgsmål

    What is a solution?

    Svar

    A homogeneous mixture. Its components are uniformly distributed at the molecular or ionic level.

  336. Kort 336

    Spørgsmål

    How do solute and solvent differ?

    Svar

    The solute is dissolved; the solvent is the dissolving medium. The solvent is often present in greater amount.

  337. Kort 337

    Spørgsmål

    What does aqueous mean in chemistry?

    Svar

    Dissolved in water. The symbol (aq) marks an aqueous species in an equation.

  338. Kort 338

    Spørgsmål

    What does concentration describe?

    Svar

    The amount of solute in a given amount of solution or solvent. Different units express it in different ways.

  339. Kort 339

    Spørgsmål

    What is molarity?

    Svar

    Moles of solute per liter of solution. Its unit is mol/L, written M.

  340. Kort 340

    Spørgsmål

    What is the molarity of 0.50 mol solute in 2.0 L of solution?

    Svar

    0.25 M. Divide 0.50 mol by 2.0 L.

  341. Kort 341

    Spørgsmål

    What stays constant when water is added to dilute a solution without reaction?

    Svar

    The moles of solute. Volume increases and concentration decreases.

  342. Kort 342

    Spørgsmål

    Which equation relates concentration and volume before and after a dilution?

    Svar

    M₁V₁ = M₂V₂. It follows from conserving the amount of solute.

  343. Kort 343

    Spørgsmål

    What is solubility?

    Svar

    The maximum concentration of a solute that can be achieved in a solution at equilibrium under specified conditions. Temperature and the substances involved matter.

  344. Kort 344

    Spørgsmål

    What is a saturated solution?

    Svar

    A solution holding the maximum dissolved solute at those conditions. Extra solute remains undissolved at equilibrium.

  345. Kort 345

    Spørgsmål

    What is an electrolyte?

    Svar

    A substance that produces mobile ions in solution and conducts electricity. Soluble ionic compounds are common examples.

  346. Kort 346

    Spørgsmål

    What does 'like dissolves like' predict?

    Svar

    Substances with similar polarity tend to mix well. Polar solvents favor polar or ionic solutes; nonpolar solvents favor nonpolar solutes.

  347. Kort 347

    Spørgsmål

    Does heating always increase solubility?

    Svar

    No. Many solids become more soluble in water, but gases usually become less soluble as temperature rises.

  348. Kort 348

    Spørgsmål

    What is an unsaturated solution?

    Svar

    A solution that can dissolve more solute at the stated conditions. It is below the solubility limit.

  349. Kort 349

    Spørgsmål

    What does a Brønsted-Lowry acid donate?

    Svar

    A proton, H⁺. In water, acid behavior increases hydronium-ion concentration.

  350. Kort 350

    Spørgsmål

    What does pH describe?

    Svar

    The hydronium-ion concentration on a logarithmic scale. Lower pH means higher hydronium concentration.

  351. Kort 351

    Spørgsmål

    At 25 °C, what pH range is acidic?

    Svar

    Below 7. A neutral aqueous solution is pH 7 at this temperature.

  352. Kort 352

    Spørgsmål

    How does hydronium concentration change when pH drops by 1 unit?

    Svar

    It increases tenfold. The pH scale is logarithmic.

  353. Kort 353

    Spørgsmål

    What does a Brønsted-Lowry base accept?

    Svar

    A proton, H⁺. Many bases in water also increase hydroxide-ion concentration.

  354. Kort 354

    Spørgsmål

    At 25 °C, what is the relationship between pH and pOH?

    Svar

    pH + pOH = 14. pOH is the negative base-10 logarithm of hydroxide-ion concentration; this relation applies to aqueous solutions at 25 °C.

  355. Kort 355

    Spørgsmål

    At 25 °C, what pH range is basic?

    Svar

    Above 7. Basic solutions have less hydronium and more hydroxide than neutral water.

  356. Kort 356

    Spørgsmål

    What are typical products of a strong acid reacting with a strong base?

    Svar

    Water and an ionic salt. Hydrogen ions and hydroxide ions combine to form water.

  357. Kort 357

    Spørgsmål

    What does strong mean for an acid or base?

    Svar

    It produces its characteristic ions essentially completely in water. Strong acids ionize; soluble ionic strong bases dissociate. Strength is separate from concentration.

  358. Kort 358

    Spørgsmål

    What does a buffer do?

    Svar

    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⁻.

  359. Kort 359

    Spørgsmål

    How does an acid-base indicator work?

    Svar

    Its color depends on pH. The change occurs over a characteristic pH range.

  360. Kort 360

    Spørgsmål

    A solution has pH 9 at 25 °C. What is its pOH?

    Svar

    5. Subtract the pH from 14.

  361. Kort 361

    Spørgsmål

    How does a concentrated weak acid differ from a dilute strong acid?

    Svar

    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.

  362. Kort 362

    Spørgsmål

    What is the SI base unit of length?

    Svar

    The meter (m). Centimeters and millimeters are decimal subdivisions of a meter.

  363. Kort 363

    Spørgsmål

    Which tool directly measures mass in a laboratory?

    Svar

    A balance. A spring scale measures force, often reported as weight.

  364. Kort 364

    Spørgsmål

    What is the SI base unit of mass?

    Svar

    The kilogram (kg). Laboratory mass is also commonly reported in grams.

  365. Kort 365

    Spørgsmål

    A student needs to measure about 35 mL of liquid and can choose a beaker or graduated cylinder. Which should they use?

    Svar

    A graduated cylinder. Read the scale at eye level.

  366. Kort 366

    Spørgsmål

    What is the SI base unit of time?

    Svar

    The second (s). Minutes and hours are accepted for many everyday uses.

  367. Kort 367

    Spørgsmål

    Where should the volume of a clear water-based liquid be read in a graduated cylinder?

    Svar

    At the bottom of the meniscus. Keep your eye level with the liquid surface.

  368. Kort 368

    Spørgsmål

    What is the SI base unit of thermodynamic temperature?

    Svar

    The kelvin (K). Degrees Celsius are widely used for laboratory and body temperatures.

  369. Kort 369

    Spørgsmål

    Which tool measures temperature?

    Svar

    A thermometer. Its range and resolution should match the task.

  370. Kort 370

    Spørgsmål

    What factor does the metric prefix kilo- represent?

    Svar

    One thousand, or 10³. One kilometer equals 1,000 meters.

  371. Kort 371

    Spørgsmål

    A ruler's smallest marking is 1 mm. To what place should a careful analog reading usually be estimated?

    Svar

    One place beyond the smallest marking, when the scale allows it. The final digit is uncertain.

  372. Kort 372

    Spørgsmål

    What is measurement accuracy?

    Svar

    Closeness to an accepted or true value. A systematic error can make precise measurements inaccurate.

  373. Kort 373

    Spørgsmål

    How do mass and weight differ?

    Svar

    Mass is the amount of matter; weight is gravitational force on that mass. Mass stays constant when gravity changes, but weight does not.

  374. Kort 374

    Spørgsmål

    What factor does the metric prefix milli- represent?

    Svar

    One thousandth, or 10⁻³. One milliliter is 0.001 liter.

  375. Kort 375

    Spørgsmål

    How can the volume of an irregular solid be measured with water?

    Svar

    Use water displacement. Subtract the initial water volume from the final volume after submerging the object.

  376. Kort 376

    Spørgsmål

    What is measurement precision?

    Svar

    Closeness of repeated measurements to one another. Precise results can still be consistently wrong.

  377. Kort 377

    Spørgsmål

    What is an instrument's resolution?

    Svar

    The smallest change it can meaningfully display or distinguish. Higher resolution does not automatically guarantee accuracy.

  378. Kort 378

    Spørgsmål

    How many centimeters are in 2.5 meters?

    Svar

    2.5 × 10² cm (250 cm). Multiply meters by the exact conversion factor 100 cm/m.

  379. Kort 379

    Spørgsmål

    Why must a numerical measurement include a unit?

    Svar

    The unit identifies the quantity's scale. A bare number is ambiguous and cannot be compared reliably.

  380. Kort 380

    Spørgsmål

    What is a scientific observation?

    Svar

    Information recorded with senses or instruments. It should be distinguished from an explanation of what was observed.

  381. Kort 381

    Spørgsmål

    What makes a hypothesis scientifically useful?

    Svar

    It is testable and falsifiable. Evidence must be able to count against it.

  382. Kort 382

    Spørgsmål

    What is a scientific theory?

    Svar

    A broad, well-supported explanation of natural phenomena. It is not a casual guess and can be revised with new evidence.

  383. Kort 383

    Spørgsmål

    Which claim is falsifiable: 'No possible observation could count against this treatment's effectiveness' or 'This treatment lowers mean temperature within one hour'?

    Svar

    The claim that the treatment lowers mean temperature within one hour. An observation could count against it, so evidence can test it.

  384. Kort 384

    Spørgsmål

    What is an inference?

    Svar

    A logical interpretation based on observations and prior knowledge. It goes beyond the raw measurement.

  385. Kort 385

    Spørgsmål

    How does a prediction relate to a hypothesis?

    Svar

    It states an expected result if the hypothesis is correct. Experiments compare observed results with that expectation.

  386. Kort 386

    Spørgsmål

    How does a scientific law differ from a scientific theory?

    Svar

    A law describes a consistent pattern; a theory explains how or why patterns occur. One does not mature into the other.

  387. Kort 387

    Spørgsmål

    What does reliability mean for a measurement or procedure?

    Svar

    It produces consistent results under the same conditions. Repetition helps assess reliability.

  388. Kort 388

    Spørgsmål

    What does a correlation show?

    Svar

    Two variables change together in a patterned way. Correlation alone does not establish that one causes the other.

  389. Kort 389

    Spørgsmål

    What is bias in scientific work?

    Svar

    A systematic influence that pushes observations, selection, or interpretation in one direction. Good design tries to prevent or measure it.

  390. Kort 390

    Spørgsmål

    What is the purpose of scientific peer review?

    Svar

    Independent experts evaluate methods, reasoning, and reporting before publication. It improves scrutiny but does not guarantee truth.

  391. Kort 391

    Spørgsmål

    What does validity ask about a study or measurement?

    Svar

    Whether it measures or tests what it claims to measure or test. Consistency alone does not ensure validity.

  392. Kort 392

    Spørgsmål

    What evidence most strengthens a causal claim?

    Svar

    A well-controlled experiment that manipulates the suspected cause. Random assignment reduces confounding, while independent replication tests whether the result holds with new data.

  393. Kort 393

    Spørgsmål

    What is a primary scientific source?

    Svar

    A report of original methods, data, and results. A review article synthesizes many primary studies.

  394. Kort 394

    Spørgsmål

    How should an unexpected outlier be handled?

    Svar

    Investigate and report it rather than deleting it automatically. Exclusion needs a documented scientific reason.

  395. Kort 395

    Spørgsmål

    What is a confounding variable?

    Svar

    An outside factor related to both the suspected cause and the outcome. It can create a misleading association.

  396. Kort 396

    Spørgsmål

    Why should a sample represent the population of interest?

    Svar

    Results generalize poorly when important groups are missing or overrepresented. Sampling method matters as much as size.

  397. Kort 397

    Spørgsmål

    What is a scientific model?

    Svar

    A simplified representation used to explain or predict a system. A model is useful within its assumptions and limits.

  398. Kort 398

    Spørgsmål

    Why should measurements report uncertainty or reasonable precision?

    Svar

    Every measurement has limits. Reporting more digits than the method supports creates false precision.

  399. Kort 399

    Spørgsmål

    If results match a prediction once, what is the safest conclusion?

    Svar

    The results support the hypothesis under those conditions. One result does not prove the hypothesis in every setting.

  400. Kort 400

    Spørgsmål

    What is a direct relationship between two variables?

    Svar

    As one increases, the other tends to increase; as one decreases, the other tends to decrease. The relationship need not be perfectly linear.

  401. Kort 401

    Spørgsmål

    Which variable is usually placed on the x-axis of an experimental graph?

    Svar

    The independent variable. It is the factor selected or changed by the investigator.

  402. Kort 402

    Spørgsmål

    What does the slope of a straight-line graph represent?

    Svar

    Change in y divided by change in x. It is the response rate per unit change in the other variable.

  403. Kort 403

    Spørgsmål

    A line rises 12 units in y while x rises 3 units. What is its slope?

    Svar

    4 units of y per unit of x. Divide 12 by 3.

  404. Kort 404

    Spørgsmål

    What is an inverse relationship?

    Svar

    As one variable increases, the other tends to decrease. Their product is constant only in a strictly inverse proportion.

  405. Kort 405

    Spørgsmål

    Which variable is usually placed on the y-axis of an experimental graph?

    Svar

    The dependent variable. It is the measured response.

  406. Kort 406

    Spørgsmål

    What does a plateau on a response graph indicate?

    Svar

    The measured response has stopped changing much despite further x increases. A limiting factor may have been reached.

  407. Kort 407

    Spørgsmål

    What is interpolation?

    Svar

    Estimating a value within the range of measured data. It is generally safer than extrapolating beyond that range.

  408. Kort 408

    Spørgsmål

    What pattern suggests no relationship between two plotted variables?

    Svar

    The response shows no consistent change as the other variable changes. Points may scatter without a trend.

  409. Kort 409

    Spørgsmål

    Before comparing values in a data table, what should you check?

    Svar

    Headings, units, and conditions. Numbers from different measures or scales cannot be compared directly.

  410. Kort 410

    Spørgsmål

    If 3 samples require 12 mL total, how much is needed for 5 equal samples?

    Svar

    20 mL. The rate is 4 mL per sample, so multiply by 5.

  411. Kort 411

    Spørgsmål

    How is the arithmetic mean calculated?

    Svar

    Add all values and divide by the number of values. A large outlier can shift the mean.

  412. Kort 412

    Spørgsmål

    Why is extrapolation uncertain?

    Svar

    It assumes the observed trend continues outside measured conditions. The relationship may change beyond the data range.

  413. Kort 413

    Spørgsmål

    A culture grows from 20 to 50 cells in 6 hours. What is the average growth rate?

    Svar

    5 cells per hour. The change is 30 cells divided by 6 hours.

  414. Kort 414

    Spørgsmål

    A measurement rises from 40 to 50. What is the percent increase?

    Svar

    25%. The increase is 10, and 10 ÷ 40 × 100 = 25%.

  415. Kort 415

    Spørgsmål

    When can the median describe a typical value better than the mean?

    Svar

    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.

  416. Kort 416

    Spørgsmål

    How do quantitative and qualitative data differ?

    Svar

    Quantitative data are numerical; qualitative data describe categories or qualities. Both can answer scientific questions.

  417. Kort 417

    Spørgsmål

    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?

    Svar

    6. The observed rate is 2 response units per dose unit, so interpolation at dose 3 gives 6.

  418. Kort 418

    Spørgsmål

    How can a graph reveal a nonlinear relationship?

    Svar

    The points follow a curve rather than a straight line. The rate of change varies across the x-range.

  419. Kort 419

    Spørgsmål

    What is the range of a data set?

    Svar

    Maximum minus minimum. It describes total spread but ignores the distribution between the endpoints.

  420. Kort 420

    Spørgsmål

    What makes a scientific research question testable?

    Svar

    It identifies measurable variables or observable outcomes. The needed data must be obtainable.

  421. Kort 421

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    In an experiment, what is the independent variable?

    Svar

    The factor deliberately changed or assigned by the investigator. In a simple one-factor experiment, changing one independent variable helps isolate its effect.

  422. Kort 422

    Spørgsmål

    What should a hypothesis connect?

    Svar

    A proposed explanation with a measurable outcome. It should lead to a prediction that evidence can challenge.

  423. Kort 423

    Spørgsmål

    What is a controlled variable, or constant?

    Svar

    A condition kept the same across groups. Holding it constant prevents it from explaining outcome differences.

  424. Kort 424

    Spørgsmål

    What is the purpose of a control group?

    Svar

    It provides a comparison without the experimental treatment. Differences can then be attributed more confidently to the treatment.

  425. Kort 425

    Spørgsmål

    In an experiment, what is the dependent variable?

    Svar

    The measured response. It may change because of the independent variable.

  426. Kort 426

    Spørgsmål

    What form can a useful experimental prediction take?

    Svar

    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.

  427. Kort 427

    Spørgsmål

    What does a positive control demonstrate?

    Svar

    That the setup can produce a known response. If it fails, the test system may be defective.

  428. Kort 428

    Spørgsmål

    Why randomly assign subjects to experimental groups?

    Svar

    To distribute known and unknown differences more evenly. This reduces selection bias and confounding.

  429. Kort 429

    Spørgsmål

    How can blinding reduce bias?

    Svar

    It keeps participants, observers, or both unaware of treatment assignments. Expectations are less likely to affect behavior or measurement.

  430. Kort 430

    Spørgsmål

    What is a placebo?

    Svar

    An inactive treatment designed to resemble the experimental treatment. It helps separate treatment effects from expectation effects.

  431. Kort 431

    Spørgsmål

    What does a negative control demonstrate?

    Svar

    What happens when the tested cause is absent. An unexpected response may reveal contamination or another source.

  432. Kort 432

    Spørgsmål

    Why does a larger sample often improve a study?

    Svar

    It reduces the influence of chance variation and supports more stable estimates. It cannot repair a biased sampling method.

  433. Kort 433

    Spørgsmål

    Why repeat trials within an experiment?

    Svar

    To estimate variability and check consistency. One unusual trial then has less influence.

  434. Kort 434

    Spørgsmål

    Why must an experimental procedure be detailed and standardized?

    Svar

    So groups are treated consistently and others can reproduce the work. Uncontrolled procedural differences create alternative explanations.

  435. Kort 435

    Spørgsmål

    Why calibrate a measuring instrument before collecting data?

    Svar

    To compare its readings with a known standard and reduce systematic error. Calibration improves confidence in accuracy.

  436. Kort 436

    Spørgsmål

    What is an operational definition?

    Svar

    A precise statement of how a variable is measured or manipulated. It turns an abstract concept into a repeatable procedure.

  437. Kort 437

    Spørgsmål

    How does independent replication differ from repeated trials?

    Svar

    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.

  438. Kort 438

    Spørgsmål

    Why should raw data be recorded before interpretation?

    Svar

    It preserves the observations separately from conclusions. Others can check calculations and reasoning.

  439. Kort 439

    Spørgsmål

    What should a scientific conclusion do?

    Svar

    Answer the research question using the data and acknowledge limits. It should not claim more than the design supports.

  440. Kort 440

    Spørgsmål

    What should happen when data do not support a hypothesis?

    Svar

    Revise or reject the hypothesis and consider new tests. Data should not be altered to preserve the original idea.

  441. Kort 441

    Spørgsmål

    What is a study limitation?

    Svar

    A feature that restricts interpretation or generalization. Small samples, short duration, and imperfect measurements are examples.

  442. Kort 442

    Spørgsmål

    Why are ethics part of experimental design?

    Svar

    Research must protect participants, organisms, and communities while balancing risks and benefits. Consent and humane treatment are key examples.

  443. Kort 443

    Spørgsmål

    How does an observational study differ from an experiment?

    Svar

    It measures variables without assigning the exposure. It can find associations but usually supports weaker causal conclusions.

  444. Kort 444

    Spørgsmål

    Plants receive 0, 2, or 4 hours of added light, and growth is measured. What is the independent variable?

    Svar

    Hours of added light. Plant growth is the dependent variable.

  445. Kort 445

    Spørgsmål

    A fertilizer study gives every plant the same water, soil, and temperature. What are these conditions?

    Svar

    Controlled variables. Keeping them constant isolates the fertilizer's effect.

  446. Kort 446

    Spørgsmål

    A drug group improves more than a control group, but the groups were not randomly assigned. What is the main caution?

    Svar

    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 kort

ATI TEAS 7 Science Flashcards: A&P, Biology, Chemistry & Scientific Reasoning

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