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