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