What posture defines the standard anatomical position?

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

In anatomical language, what does superior mean?

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

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

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

Why does the body use feedback mechanisms?

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

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

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

What does anterior mean in human anatomy?

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

Which plane divides the body into upper and lower portions?

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

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

Which major body cavity contains the brain and spinal cord?

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

What does medial mean in anatomical language?

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

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

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

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

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

Which major body cavity contains the thoracic and abdominopelvic cavities?

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

What does proximal mean when describing a limb?

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

How does positive feedback differ from negative feedback?

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

Which tissue type covers surfaces and lines body cavities?

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

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

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

What shared property lets muscle tissue produce movement?

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

Which tissue type rapidly communicates by electrical signals?

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

Why are tightly packed epithelial cells well suited for barriers?

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

What distinguishes connective tissue from epithelial tissue?

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

What are the four basic human tissue types?

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

What makes a structure an organ rather than a tissue?

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

What are the skeletal system's main functions?

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

What belongs to the axial skeleton?

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

How do compact and spongy bone differ?

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

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

Which bone cell builds new bone matrix?

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

What belongs to the appendicular skeleton?

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

What is the main role of red bone marrow?

Blood-cell production. This process is called hematopoiesis.

Which joint class allows the greatest range of motion?

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

Which bone cell breaks down bone matrix?

An osteoclast. Bone resorption helps remodeling and mineral balance.

What does a ligament connect?

Bone to bone. A tendon connects muscle to bone.

What is the shaft of a long bone called?

The diaphysis. The enlarged ends are the epiphyses.

Why is bone important to blood-calcium balance?

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

What is stored mainly in yellow bone marrow?

Fat. It serves as an energy reserve.

What does articular cartilage do at a synovial joint?

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

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

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

What is bone remodeling?

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

Which muscle tissue is usually under voluntary control?

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

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

What does a tendon connect?

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

Which proteins slide past one another during muscle contraction?

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

Where is smooth muscle commonly found?

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

What ion exposes binding sites needed for skeletal muscle contraction?

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

How do antagonistic muscle pairs move a joint?

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

Why does muscle contraction require ATP?

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

Which muscle tissue makes up the heart wall?

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

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

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

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

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

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

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

Practice 446 original ATI TEAS 7 Science recall and mini-scenario cards across A&P, biology, chemistry, and scientific reasoning.

من إعداد Flashcards Open Source App

حول هذه الرزمة

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.

بطاقات هذه الرزمة

البطاقة ١
السؤال
What posture defines the standard anatomical position?
الإجابة
Standing upright, facing forward, with arms at the sides and palms forward. The feet point forward, giving anatomy a consistent reference position.
البطاقة ٢
السؤال
In anatomical language, what does superior mean?
الإجابة
Toward the head or above another structure. Inferior means toward the feet or below.
البطاقة ٣
السؤال
Which anatomical plane divides the body into left and right portions?
الإجابة
The sagittal plane. A midsagittal plane divides the body into equal left and right halves.
البطاقة ٤
السؤال
Why does the body use feedback mechanisms?
الإجابة
To regulate internal conditions. Feedback compares a condition with a set range and triggers responses that adjust it.
البطاقة ٥
السؤال
What is the order of structural organization from simplest to most complex?
الإجابة
Chemical, cellular, tissue, organ, organ system, organism. Each level builds on interactions at the preceding level.
البطاقة ٦
السؤال
What does anterior mean in human anatomy?
الإجابة
Toward the front of the body. Posterior means toward the back.
البطاقة ٧
السؤال
Which plane divides the body into upper and lower portions?
الإجابة
The transverse plane. It is also called the horizontal plane.
البطاقة ٨
السؤال
What is homeostasis?
الإجابة
The maintenance of a relatively stable internal environment. It is dynamic rather than perfectly unchanging.
البطاقة ٩
السؤال
Which major body cavity contains the brain and spinal cord?
الإجابة
The dorsal body cavity. Its cranial cavity holds the brain, and its vertebral cavity holds the spinal cord.
البطاقة ١٠
السؤال
What does medial mean in anatomical language?
الإجابة
Toward the body's midline. Lateral means farther from the midline.
البطاقة ١١
السؤال
A rise in body temperature triggers sweating. What control pattern is this?
الإجابة
Negative feedback. The response opposes the original temperature change and moves the body toward its normal range.
البطاقة ١٢
السؤال
Which anatomical plane divides the body into front and back portions?
الإجابة
The frontal, or coronal, plane. It separates anterior from posterior portions.
البطاقة ١٣
السؤال
Which major body cavity contains the thoracic and abdominopelvic cavities?
الإجابة
The ventral body cavity. The diaphragm separates its thoracic and abdominopelvic portions.
البطاقة ١٤
السؤال
What does proximal mean when describing a limb?
الإجابة
Closer to the limb's point of attachment. Distal means farther from that point.
البطاقة ١٥
السؤال
How does positive feedback differ from negative feedback?
الإجابة
Positive feedback amplifies the initial change. Negative feedback opposes a change; positive feedback continues until a stopping event occurs.
البطاقة ١٦
السؤال
Which tissue type covers surfaces and lines body cavities?
الإجابة
Epithelial tissue. It also forms many glands and often serves protective, absorptive, or secretory roles.
البطاقة ١٧
السؤال
Which tissue type mainly supports, binds, and protects other tissues?
الإجابة
Connective tissue. Its cells are typically separated by an extracellular matrix.
البطاقة ١٨
السؤال
What shared property lets muscle tissue produce movement?
الإجابة
Contractility. Muscle cells shorten or develop tension in response to stimulation.
البطاقة ١٩
السؤال
Which tissue type rapidly communicates by electrical signals?
الإجابة
Nervous tissue. Neurons transmit signals, while supporting cells help maintain their environment.
البطاقة ٢٠
السؤال
Why are tightly packed epithelial cells well suited for barriers?
الإجابة
They leave little space between cells. This continuous arrangement limits passage across a surface.
البطاقة ٢١
السؤال
What distinguishes connective tissue from epithelial tissue?
الإجابة
Connective tissue usually has abundant extracellular matrix. Epithelial cells are more tightly packed.
البطاقة ٢٢
السؤال
What are the four basic human tissue types?
الإجابة
Epithelial, connective, muscle, and nervous tissue. Organs contain two or more tissue types working together.
البطاقة ٢٣
السؤال
What makes a structure an organ rather than a tissue?
الإجابة
An organ combines multiple tissue types for a specific function. A tissue is a group of similar cells and matrix performing related work.
البطاقة ٢٤
السؤال
What are the skeletal system's main functions?
الإجابة
Support, protection, movement, mineral storage, blood-cell production, and fat storage. Bones also provide levers for muscles.
البطاقة ٢٥
السؤال
What belongs to the axial skeleton?
الإجابة
The skull, vertebral column, and thoracic cage. These structures form the body's central axis.
البطاقة ٢٦
السؤال
How do compact and spongy bone differ?
الإجابة
Compact bone is dense; spongy bone has a lattice of trabeculae. Both are organized living bone tissue.
البطاقة ٢٧
السؤال
What is a joint?
الإجابة
A place where two or more bones meet. Joint structure determines how much movement is possible.
البطاقة ٢٨
السؤال
Which bone cell builds new bone matrix?
الإجابة
An osteoblast. Osteoclasts break down bone, while osteocytes maintain mature bone tissue.
البطاقة ٢٩
السؤال
What belongs to the appendicular skeleton?
الإجابة
The limbs plus the shoulder and pelvic girdles. It attaches the limbs to the axial skeleton.
البطاقة ٣٠
السؤال
What is the main role of red bone marrow?
الإجابة
Blood-cell production. This process is called hematopoiesis.
البطاقة ٣١
السؤال
Which joint class allows the greatest range of motion?
الإجابة
A synovial joint. A fluid-filled joint cavity reduces friction between articulating surfaces.
البطاقة ٣٢
السؤال
Which bone cell breaks down bone matrix?
الإجابة
An osteoclast. Bone resorption helps remodeling and mineral balance.
البطاقة ٣٣
السؤال
What does a ligament connect?
الإجابة
Bone to bone. A tendon connects muscle to bone.
البطاقة ٣٤
السؤال
What is the shaft of a long bone called?
الإجابة
The diaphysis. The enlarged ends are the epiphyses.
البطاقة ٣٥
السؤال
Why is bone important to blood-calcium balance?
الإجابة
Bone stores calcium and can release or absorb it during remodeling. Hormones regulate this exchange.
البطاقة ٣٦
السؤال
What is stored mainly in yellow bone marrow?
الإجابة
Fat. It serves as an energy reserve.
البطاقة ٣٧
السؤال
What does articular cartilage do at a synovial joint?
الإجابة
It reduces friction and absorbs shock. It covers the ends of articulating bones.
البطاقة ٣٨
السؤال
Why must a broken bone receive a blood supply during healing?
الإجابة
Repairing cells need oxygen and nutrients. Restored blood vessels support fracture healing.
البطاقة ٣٩
السؤال
What is bone remodeling?
الإجابة
Continuous removal and replacement of bone tissue. It repairs microdamage and helps bones adapt to stress.
البطاقة ٤٠
السؤال
Which muscle tissue is usually under voluntary control?
الإجابة
Skeletal muscle. Most skeletal muscles move the skeleton, while some, such as facial muscles, insert into skin or other soft tissue.
البطاقة ٤١
السؤال
What is a sarcomere?
الإجابة
The basic contractile unit of striated muscle. It lies between two Z discs.
البطاقة ٤٢
السؤال
What does a tendon connect?
الإجابة
Muscle to bone. It transmits muscle force to the skeleton.
البطاقة ٤٣
السؤال
Which proteins slide past one another during muscle contraction?
الإجابة
Actin and myosin. Their interaction shortens sarcomeres without shortening the filaments themselves.
البطاقة ٤٤
السؤال
Where is smooth muscle commonly found?
الإجابة
In the walls of hollow organs and blood vessels. Its contractions are generally involuntary.
البطاقة ٤٥
السؤال
What ion exposes binding sites needed for skeletal muscle contraction?
الإجابة
Calcium. Its release inside the muscle fiber allows actin and myosin interaction.
البطاقة ٤٦
السؤال
How do antagonistic muscle pairs move a joint?
الإجابة
One muscle contracts while the opposing muscle relaxes. Reversing their roles moves the joint in the opposite direction.
البطاقة ٤٧
السؤال
Why does muscle contraction require ATP?
الإجابة
ATP powers cross-bridge cycling and ion pumps. It is also needed for myosin to detach from actin.
البطاقة ٤٨
السؤال
Which muscle tissue makes up the heart wall?
الإجابة
Cardiac muscle. It is striated, involuntary, and connected for coordinated pumping.
البطاقة ٤٩
السؤال
During a typical muscle contraction, which attachment moves more: origin or insertion?
الإجابة
The insertion. The origin is generally the more fixed attachment.
البطاقة ٥٠
السؤال
Which type of neuron sends the signal that initiates skeletal-muscle contraction?
الإجابة
A somatic motor neuron. It releases acetylcholine at the neuromuscular junction, triggering an action potential in the muscle fiber.
البطاقة ٥١
السؤال
What is muscle tone?
الإجابة
Continuous low-level muscle tension. It helps maintain posture and readiness without producing a large movement.
البطاقة ٥٢
السؤال
How does skeletal muscle help regulate body temperature?
الإجابة
Contraction releases heat. Shivering increases rapid contractions when the body is cold.
البطاقة ٥٣
السؤال
What are the three muscle tissue types?
الإجابة
Skeletal, cardiac, and smooth muscle. They differ in location, structure, and control.
البطاقة ٥٤
السؤال
What is a neuron's main function?
الإجابة
To receive, process, and transmit information. Neurons use electrical signals and chemical messengers.
البطاقة ٥٥
السؤال
What structures make up the central nervous system?
الإجابة
The brain and spinal cord. They integrate information and coordinate responses.
البطاقة ٥٦
السؤال
Which part of a neuron usually receives incoming signals?
الإجابة
The dendrites. The cell body integrates much of that input.
البطاقة ٥٧
السؤال
What does the peripheral nervous system include?
الإجابة
Nerves and ganglia outside the brain and spinal cord. It links the central nervous system with the rest of the body.
البطاقة ٥٨
السؤال
Which neuron structure carries an impulse away from the cell body?
الإجابة
The axon. Its terminals communicate with another cell.
البطاقة ٥٩
السؤال
Which nervous-system division controls skeletal muscles voluntarily?
الإجابة
The somatic nervous system. It also carries sensory information from skin, muscles, and joints.
البطاقة ٦٠
السؤال
What is a synapse?
الإجابة
A junction where one neuron communicates with another cell. Chemical synapses use neurotransmitters across a small gap.
البطاقة ٦١
السؤال
Which nervous-system division regulates organs and glands without conscious control?
الإجابة
The autonomic nervous system. It includes sympathetic and parasympathetic divisions.
البطاقة ٦٢
السؤال
How does myelin affect nerve signaling?
الإجابة
It speeds impulse conduction along an axon. Myelin insulates segments of the axon.
البطاقة ٦٣
السؤال
Which autonomic division prepares the body for acute activity?
الإجابة
The sympathetic division. It generally increases alertness and supports a fight-or-flight response.
البطاقة ٦٤
السؤال
What is a reflex?
الإجابة
A rapid, predictable response to a stimulus. A reflex pathway can act before conscious awareness.
البطاقة ٦٥
السؤال
Which autonomic division supports rest, digestion, and energy conservation?
الإجابة
The parasympathetic division. It generally promotes routine maintenance functions.
البطاقة ٦٦
السؤال
Which brain region is most associated with conscious thought and voluntary movement?
الإجابة
The cerebrum. Its cortex also processes much sensory information.
البطاقة ٦٧
السؤال
Which brain region fine-tunes balance and coordinated movement?
الإجابة
The cerebellum. It compares intended movement with sensory feedback.
البطاقة ٦٨
السؤال
Which brain region controls vital automatic functions such as breathing and heart rate?
الإجابة
The brainstem. It also connects higher brain regions with the spinal cord.
البطاقة ٦٩
السؤال
How do sensory and motor neurons differ?
الإجابة
Sensory neurons carry information toward the CNS; motor neurons carry commands away. Interneurons connect and process signals within the CNS.
البطاقة ٧٠
السؤال
What does a sensory receptor do?
الإجابة
It converts a stimulus into a neural signal. Different receptors respond best to particular forms of energy or chemicals.
البطاقة ٧١
السؤال
What is a hormone?
الإجابة
A chemical messenger released into body fluids to affect target cells. A target responds only if it has the appropriate receptor.
البطاقة ٧٢
السؤال
Why is the pituitary gland often called a master gland?
الإجابة
Several pituitary hormones regulate other endocrine glands. The hypothalamus controls much of pituitary activity.
البطاقة ٧٣
السؤال
Why can one hormone affect some cells but not others?
الإجابة
Only target cells have the matching receptor. Receptor binding starts the cell's response.
البطاقة ٧٤
السؤال
Which gland produces hormones that broadly increase metabolic activity?
الإجابة
The thyroid gland. Thyroid hormones influence energy use and development.
البطاقة ٧٥
السؤال
What is insulin's main effect on blood glucose?
الإجابة
It lowers blood glucose. Insulin promotes glucose uptake and storage after a meal.
البطاقة ٧٦
السؤال
Which glands release a hormone that raises blood calcium?
الإجابة
The parathyroid glands. Parathyroid hormone acts on bone, kidneys, and vitamin D pathways.
البطاقة ٧٧
السؤال
Which adrenal region releases epinephrine during acute stress?
الإجابة
The adrenal medulla. Its hormones reinforce sympathetic nervous-system effects.
البطاقة ٧٨
السؤال
Which organ has both endocrine and digestive functions?
الإجابة
The pancreas. Its islets release hormones, while other cells release digestive enzymes.
البطاقة ٧٩
السؤال
What is glucagon's main effect on blood glucose?
الإجابة
It raises blood glucose. It promotes release of stored glucose during fasting.
البطاقة ٨٠
السؤال
Rising thyroid hormone reduces its own upstream stimulation. What pattern is this?
الإجابة
Negative feedback. The final hormone limits further release along the control pathway.
البطاقة ٨١
السؤال
Which adrenal region produces steroid hormones such as cortisol and aldosterone?
الإجابة
The adrenal cortex. It surrounds the adrenal medulla.
البطاقة ٨٢
السؤال
Which gland releases melatonin and helps regulate daily sleep timing?
الإجابة
The pineal gland. Light information influences its secretion pattern.
البطاقة ٨٣
السؤال
Which hormone directly increases collecting-duct water permeability?
الإجابة
Antidiuretic hormone, or ADH. It makes collecting ducts more permeable to water, increasing water reabsorption and usually producing less, more concentrated urine.
البطاقة ٨٤
السؤال
Which hormone strengthens uterine contractions during labor?
الإجابة
Oxytocin. This is a classic positive-feedback pathway that ends after delivery.
البطاقة ٨٥
السؤال
How does endocrine signaling generally differ from nervous signaling?
الإجابة
It is usually slower to start and longer lasting. Hormones travel through body fluids, while neurons signal specific targets rapidly.
البطاقة ٨٦
السؤال
What is plasma?
الإجابة
The liquid portion of blood. It carries cells, nutrients, hormones, proteins, wastes, and dissolved gases.
البطاقة ٨٧
السؤال
Which side of the heart pumps blood to the lungs?
الإجابة
The right side. The right ventricle sends deoxygenated blood through the pulmonary trunk and arteries.
البطاقة ٨٨
السؤال
What is the main function of red blood cells?
الإجابة
Transporting oxygen. Their hemoglobin also carries a smaller share of carbon dioxide.
البطاقة ٨٩
السؤال
What defines an artery?
الإجابة
It carries blood away from the heart. Oxygen content does not define it; pulmonary arteries carry deoxygenated blood.
البطاقة ٩٠
السؤال
What is the main function of white blood cells?
الإجابة
Body defense. Different white blood cells recognize, attack, or coordinate responses to threats.
البطاقة ٩١
السؤال
Which side of the heart pumps blood into systemic circulation?
الإجابة
The left side. The left ventricle sends oxygenated blood into the aorta.
البطاقة ٩٢
السؤال
What is the main purpose of heart valves?
الإجابة
To keep blood moving in one direction. Pressure differences open and close them.
البطاقة ٩٣
السؤال
What defines a vein?
الإجابة
It carries blood toward the heart. Many veins contain valves that limit backflow.
البطاقة ٩٤
السؤال
What is the main role of platelets?
الإجابة
Helping stop bleeding. They form a platelet plug and support clotting reactions at a damaged vessel.
البطاقة ٩٥
السؤال
Why are capillaries well suited for exchange?
الإجابة
Their walls are only one cell layer thick. Their small diameter and large total surface area support diffusion and filtration.
البطاقة ٩٦
السؤال
After blood enters the right atrium, what chamber receives it next?
الإجابة
The right ventricle. Blood passes through the tricuspid valve before entering that chamber.
البطاقة ٩٧
السؤال
What happens during ventricular systole?
الإجابة
The ventricles contract and eject blood. The right ventricle pumps to the lungs, and the left pumps to the body.
البطاقة ٩٨
السؤال
What is pulmonary circulation?
الإجابة
Blood flow between the heart and lungs. It allows gas exchange and returns oxygenated blood to the left atrium.
البطاقة ٩٩
السؤال
What normally sets the heart's rhythm?
الإجابة
The sinoatrial, or SA, node. Its spontaneous electrical activity initiates each heartbeat.
البطاقة ١٠٠
السؤال
What molecule in red blood cells binds oxygen?
الإجابة
Hemoglobin. Its iron-containing heme groups bind oxygen reversibly.
البطاقة ١٠١
السؤال
What happens during ventricular diastole?
الإجابة
The ventricles relax and fill. Atrioventricular valves are open during most ventricular filling.
البطاقة ١٠٢
السؤال
What is systemic circulation?
الإجابة
Blood flow between the heart and the body's tissues. It delivers oxygen and nutrients and returns wastes.
البطاقة ١٠٣
السؤال
What does arterial blood pressure measure?
الإجابة
The force of blood against artery walls. It is commonly reported as systolic over diastolic pressure.
البطاقة ١٠٤
السؤال
What do coronary arteries supply?
الإجابة
The heart muscle itself. Blocked coronary blood flow can deprive myocardium of oxygen.
البطاقة ١٠٥
السؤال
Which major vessels return systemic blood to the right atrium?
الإجابة
The superior and inferior venae cavae. The superior vessel drains the upper body; the inferior drains the lower body.
البطاقة ١٠٦
السؤال
What is the respiratory system's primary gas-exchange function?
الإجابة
Bringing oxygen into the body and removing carbon dioxide. Ventilation moves air, while diffusion exchanges gases.
البطاقة ١٠٧
السؤال
What is the airflow sequence from the pharynx to the gas-exchange surfaces?
الإجابة
Pharynx, larynx, trachea, bronchi, bronchioles, alveoli. Each branch conducts air deeper into the lungs.
البطاقة ١٠٨
السؤال
Where does most gas exchange occur in the lungs?
الإجابة
Across the alveolar-capillary membrane. Thin walls and a large surface area shorten diffusion distance.
البطاقة ١٠٩
السؤال
What does the diaphragm do during quiet inhalation?
الإجابة
It contracts and moves downward. Thoracic volume rises, lung pressure falls, and air flows inward.
البطاقة ١١٠
السؤال
Why does oxygen move from alveoli into pulmonary capillaries?
الإجابة
Its partial pressure is higher in alveolar air than in incoming blood. Oxygen diffuses down that gradient.
البطاقة ١١١
السؤال
What drives quiet exhalation?
الإجابة
Elastic recoil after inspiratory muscles relax. Thoracic volume falls and pressure pushes air outward.
البطاقة ١١٢
السؤال
What is the pleura?
الإجابة
A double membrane surrounding each lung. A thin fluid layer reduces friction during breathing.
البطاقة ١١٣
السؤال
How is most oxygen transported in blood?
الإجابة
Bound to hemoglobin in red blood cells. Only a small amount dissolves directly in plasma.
البطاقة ١١٤
السؤال
Why does carbon dioxide move from pulmonary blood into alveoli?
الإجابة
Its partial pressure is higher in incoming blood than in alveolar air. It diffuses down that gradient for exhalation.
البطاقة ١١٥
السؤال
What helps keep swallowed material out of the airway?
الإجابة
The epiglottis and coordinated swallowing reflexes. The laryngeal opening is protected as food passes.
البطاقة ١١٦
السؤال
How does the conducting airway remove trapped particles?
الإجابة
Mucus traps them, and cilia move the mucus toward the throat. This is the mucociliary escalator.
البطاقة ١١٧
السؤال
In what form is most carbon dioxide transported in blood?
الإجابة
As bicarbonate ions. Red blood cells help convert carbon dioxide and water into bicarbonate.
البطاقة ١١٨
السؤال
Which blood change is a strong normal stimulus to increase breathing?
الإجابة
A rise in carbon dioxide and the associated fall in pH. Brainstem centers adjust ventilation in response.
البطاقة ١١٩
السؤال
Why must alveoli receive both air and blood?
الإجابة
Gas exchange needs ventilation and perfusion. Air without blood flow, or blood without airflow, cannot exchange gases effectively.
البطاقة ١٢٠
السؤال
Why does ventilation increase during exercise?
الإجابة
Active tissues use more oxygen and produce more carbon dioxide. Faster, deeper breathing helps meet that demand.
البطاقة ١٢١
السؤال
What are the digestive system's core functions?
الإجابة
Ingestion, digestion, absorption, and elimination. Movement and secretion support those processes.
البطاقة ١٢٢
السؤال
What is the alimentary-canal sequence after the mouth?
الإجابة
Pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus. Food passes through this continuous tube.
البطاقة ١٢٣
السؤال
What is mechanical digestion?
الإجابة
Physical breakdown and mixing of food without changing its molecules. Chewing and stomach churning are examples.
البطاقة ١٢٤
السؤال
What are two major functions of the stomach?
الإجابة
It stores and mixes food and begins substantial protein digestion. Acid denatures proteins, converts pepsinogen to pepsin, and provides the low pH pepsin needs.
البطاقة ١٢٥
السؤال
Where does most nutrient absorption occur?
الإجابة
The small intestine. Folds, villi, and microvilli create a large absorptive surface.
البطاقة ١٢٦
السؤال
Which nutrient does salivary amylase begin digesting in the mouth?
الإجابة
Carbohydrates, especially starch. Salivary amylase breaks starch into smaller carbohydrates.
البطاقة ١٢٧
السؤال
What is chemical digestion?
الإجابة
Enzymatic breakdown of large food molecules into absorbable units. Chemical bonds are changed during the process.
البطاقة ١٢٨
السؤال
What is peristalsis?
الإجابة
Wave-like smooth-muscle contractions that move material forward. It occurs throughout much of the digestive tract.
البطاقة ١٢٩
السؤال
What is a main function of the large intestine?
الإجابة
Absorbing water and electrolytes and forming feces. Resident microbes also process some undigested material.
البطاقة ١٣٠
السؤال
What digestive product does the liver make?
الإجابة
Bile. Bile salts help disperse dietary fat into smaller droplets.
البطاقة ١٣١
السؤال
What does a digestive sphincter do?
الإجابة
It regulates movement between regions of the digestive tract. Circular muscle contracts to close a passage.
البطاقة ١٣٢
السؤال
What does the pancreas release into the small intestine?
الإجابة
Digestive enzymes and bicarbonate-rich fluid. Bicarbonate helps neutralize acidic material from the stomach.
البطاقة ١٣٣
السؤال
How do intestinal villi improve absorption?
الإجابة
They increase surface area. Each villus contains blood capillaries and a lymphatic lacteal for transported nutrients.
البطاقة ١٣٤
السؤال
What is the gallbladder's role?
الإجابة
It stores and concentrates bile. It releases bile into the small intestine when fatty food arrives.
البطاقة ١٣٥
السؤال
Which macronutrient's absorbed products usually enter intestinal lacteals before reaching the blood?
الإجابة
Most dietary lipids. Their absorbed products travel through lymph before entering the bloodstream.
البطاقة ١٣٦
السؤال
Which accessory organs help digestion without food passing through them?
الإجابة
The teeth, tongue, salivary glands, liver, gallbladder, and pancreas. Teeth and the tongue act mechanically; the other accessory organs add or store digestive secretions.
البطاقة ١٣٧
السؤال
What organs make up the urinary system?
الإجابة
The kidneys, ureters, urinary bladder, and urethra. Kidneys make urine; the remaining organs transport, store, and release it.
البطاقة ١٣٨
السؤال
What is a nephron?
الإجابة
The kidney's functional unit. It filters blood and adjusts the filtrate to form urine.
البطاقة ١٣٩
السؤال
Where does blood filtration begin in a nephron?
الإجابة
At the renal corpuscle. Pressure pushes water and small solutes from glomerular capillaries into the capsule.
البطاقة ١٤٠
السؤال
What moves urine from a kidney to the bladder?
الإجابة
A ureter. Smooth-muscle contractions propel urine along the tube.
البطاقة ١٤١
السؤال
What is the urinary bladder's main role?
الإجابة
Temporary urine storage. Stretch receptors help trigger the urge to urinate as it fills.
البطاقة ١٤٢
السؤال
Which structure carries urine from the bladder out of the body?
الإجابة
The urethra. It is distinct from the ureters that enter the bladder.
البطاقة ١٤٣
السؤال
What is tubular reabsorption?
الإجابة
Movement of useful substances from nephron fluid back into blood. Water, glucose, and ions are common examples.
البطاقة ١٤٤
السؤال
What is the glomerulus?
الإجابة
A capillary tuft that filters blood in the renal corpuscle. Cells and most large proteins normally remain in circulation.
البطاقة ١٤٥
السؤال
How does more ADH change urine?
الإجابة
It makes urine more concentrated and lowers its volume. More water is reabsorbed from the collecting ducts.
البطاقة ١٤٦
السؤال
What path does filtrate follow after entering the glomerular capsule?
الإجابة
Proximal convoluted tubule → nephron loop → distal convoluted tubule → collecting duct. The collecting duct receives forming urine from multiple nephrons.
البطاقة ١٤٧
السؤال
What is tubular secretion?
الإجابة
Movement of selected substances from blood into nephron fluid. It helps eliminate wastes and regulate ions and pH.
البطاقة ١٤٨
السؤال
Besides removing waste, what does the urinary system regulate?
الإجابة
Water, electrolytes, acid-base balance, and blood volume. Kidney hormones also affect blood pressure and red-cell production.
البطاقة ١٤٩
السؤال
Why does dehydration usually reduce urine volume?
الإجابة
The body conserves water by increasing renal reabsorption. ADH is an important signal in this response.
البطاقة ١٥٠
السؤال
Why do the kidneys receive a large blood flow?
الإجابة
They must continuously filter plasma and regulate its composition. High flow supports waste removal and homeostasis.
البطاقة ١٥١
السؤال
What is lymph?
الإجابة
Interstitial fluid that has entered lymphatic vessels. It eventually returns to the bloodstream.
البطاقة ١٥٢
السؤال
What is innate immunity?
الإجابة
Rapid, nonspecific defense present before a particular exposure. Barriers, inflammation, and several immune cells contribute.
البطاقة ١٥٣
السؤال
What is a major function of lymph nodes?
الإجابة
Filtering lymph and providing sites for immune-cell activation. Swelling can reflect an active immune response.
البطاقة ١٥٤
السؤال
What does the spleen filter?
الإجابة
Blood. It removes aged blood cells and supports immune responses to blood-borne antigens.
البطاقة ١٥٥
السؤال
What is a key function of B lymphocytes?
الإجابة
Producing antibody-secreting cells and memory cells. Antibodies bind specific antigens.
البطاقة ١٥٦
السؤال
What distinguishes adaptive immunity?
الإجابة
It targets specific antigens and develops memory. Later exposure can trigger a faster, stronger response.
البطاقة ١٥٧
السؤال
Which lymphatic organ is important for T-cell maturation?
الإجابة
The thymus. It is most active early in life.
البطاقة ١٥٨
السؤال
What is the body's first physical barrier against many pathogens?
الإجابة
Intact skin and mucous membranes. Their secretions and normal microbes add protection.
البطاقة ١٥٩
السؤال
What is a key function of T lymphocytes?
الإجابة
Coordinating immune responses or killing infected cells. Different T-cell types perform different roles.
البطاقة ١٦٠
السؤال
What does an antibody bind?
الإجابة
A specific antigen. Binding can neutralize a target or mark it for other immune defenses.
البطاقة ١٦١
السؤال
What is the purpose of inflammation after tissue injury?
الإجابة
To contain damage, recruit defenses, and begin repair. Redness, heat, swelling, and pain can accompany it.
البطاقة ١٦٢
السؤال
Why is a second adaptive response often faster than the first?
الإجابة
Memory lymphocytes remain after the first exposure. They respond quickly when the same antigen appears again.
البطاقة ١٦٣
السؤال
What does a phagocyte do?
الإجابة
It engulfs particles, microbes, or debris. Neutrophils and macrophages are important examples.
البطاقة ١٦٤
السؤال
How does vaccination support adaptive immunity?
الإجابة
It safely exposes the immune system to antigen information. This promotes memory without requiring the full disease.
البطاقة ١٦٥
السؤال
Why is lymphatic fluid return important?
الإجابة
It prevents excess interstitial fluid from accumulating. Lymphatic vessels return fluid and leaked proteins to blood.
البطاقة ١٦٦
السؤال
What structures belong to the integumentary system?
الإجابة
Skin, hair, nails, sweat glands, and sebaceous glands. Together they form the body's outer covering.
البطاقة ١٦٧
السؤال
What is the epidermis?
الإجابة
The outer epithelial layer of skin. It is avascular and contains protective keratinized cells.
البطاقة ١٦٨
السؤال
How does sweating cool the body?
الإجابة
Evaporation removes heat from the skin. Skin blood-flow changes also help regulate heat loss.
البطاقة ١٦٩
السؤال
What is a major role of melanin in skin?
الإجابة
Absorbing some ultraviolet radiation. It also contributes to skin and hair color.
البطاقة ١٧٠
السؤال
How does skin contribute to sensation?
الإجابة
Sensory receptors detect touch, pressure, pain, and temperature. Nerves carry that information to the CNS.
البطاقة ١٧١
السؤال
What is the dermis?
الإجابة
The connective-tissue layer beneath the epidermis. It contains vessels, nerves, glands, and hair follicles.
البطاقة ١٧٢
السؤال
How does skin support vitamin D production?
الإجابة
Ultraviolet light starts conversion of a skin molecule into a vitamin D precursor. The liver and kidneys complete activation.
البطاقة ١٧٣
السؤال
Why does a deep skin wound bleed but a shallow epidermal scrape may not?
الإجابة
Blood vessels are in the dermis, not the epidermis. A wound must reach vascular tissue to damage them.
البطاقة ١٧٤
السؤال
What is a gamete?
الإجابة
A haploid reproductive cell. Human sperm and oocytes each carry 23 chromosomes.
البطاقة ١٧٥
السؤال
What are the testes' two main reproductive functions?
الإجابة
Producing sperm and secreting testosterone. Sperm develop in seminiferous tubules.
البطاقة ١٧٦
السؤال
What tube carries sperm from the epididymis toward the ejaculatory duct?
الإجابة
The ductus, or vas, deferens. Smooth muscle propels sperm during ejaculation.
البطاقة ١٧٧
السؤال
What is ovulation?
الإجابة
Release of a secondary oocyte from an ovary. A surge in luteinizing hormone helps trigger it.
البطاقة ١٧٨
السؤال
Where does fertilization usually occur?
الإجابة
In a uterine tube. The early embryo then travels toward the uterus.
البطاقة ١٧٩
السؤال
What are the ovaries' two main reproductive functions?
الإجابة
Producing oocytes and secreting sex hormones. Estrogen and progesterone help regulate the reproductive cycle.
البطاقة ١٨٠
السؤال
What is the uterus' main reproductive role?
الإجابة
Supporting implantation and development of an embryo and fetus. Its muscular wall also contracts during birth.
البطاقة ١٨١
السؤال
What causes menstruation when pregnancy does not occur?
الإجابة
Falling ovarian hormones allow the uterine lining to shed. A new cycle then begins.
البطاقة ١٨٢
السؤال
How does a sperm cell's structure support its function?
الإجابة
Its flagellum provides movement, and its head carries DNA plus enzymes used during fertilization. Mitochondria supply energy in the midpiece.
البطاقة ١٨٣
السؤال
What is the placenta's exchange role?
الإجابة
It allows gases, nutrients, and wastes to move between maternal and fetal circulations. Their blood normally does not mix directly.
البطاقة ١٨٤
السؤال
Why is meiosis necessary for sexual reproduction?
الإجابة
It halves chromosome number in gametes. Fertilization then restores the diploid number.
البطاقة ١٨٥
السؤال
How do sex hormones regulate reproductive control pathways?
الإجابة
They usually feed back on the hypothalamus and pituitary. This adjusts release of hormones that act on the gonads.
البطاقة ١٨٦
السؤال
What does cell theory state?
الإجابة
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.
البطاقة ١٨٧
السؤال
What is the defining structural feature of a prokaryotic cell?
الإجابة
It lacks a membrane-bound nucleus. Its DNA occupies a nucleoid region.
البطاقة ١٨٨
السؤال
What is the cell membrane's main role?
الإجابة
Regulating movement between the cell and its environment. Its phospholipid bilayer is selectively permeable.
البطاقة ١٨٩
السؤال
What is the nucleus' main role?
الإجابة
Storing most of a eukaryotic cell's DNA. Nuclear pores regulate exchange with the cytoplasm.
البطاقة ١٩٠
السؤال
Where are proteins assembled?
الإجابة
At ribosomes. Ribosomes may float in cytosol or attach to rough endoplasmic reticulum.
البطاقة ١٩١
السؤال
What distinguishes a eukaryotic cell from a prokaryotic cell?
الإجابة
A eukaryotic cell has a membrane-bound nucleus and other membrane-bound organelles. Animals, plants, fungi, and protists are eukaryotes.
البطاقة ١٩٢
السؤال
What is a mitochondrion's main function?
الإجابة
Producing most cellular ATP through aerobic respiration. Its inner membrane provides a large reaction surface.
البطاقة ١٩٣
السؤال
What does rough endoplasmic reticulum mainly produce?
الإجابة
Proteins for secretion, membranes, or organelles. Ribosomes on its surface make the proteins.
البطاقة ١٩٤
السؤال
Which organelle carries out photosynthesis in plants and algae?
الإجابة
The chloroplast. It converts light energy into chemical energy stored in organic molecules.
البطاقة ١٩٥
السؤال
What does the Golgi apparatus do?
الإجابة
It modifies, sorts, and packages cell products. Vesicles carry those products to their destinations.
البطاقة ١٩٦
السؤال
What is a lysosome's role?
الإجابة
Digesting worn cell parts and engulfed material. Its enzymes work best in an acidic interior.
البطاقة ١٩٧
السؤال
What are major functions of smooth endoplasmic reticulum?
الإجابة
Lipid synthesis, detoxification, and calcium storage. Its membrane lacks attached ribosomes.
البطاقة ١٩٨
السؤال
What does the cytoskeleton provide?
الإجابة
Cell shape, internal organization, movement, and transport tracks. It is built from protein filaments.
البطاقة ١٩٩
السؤال
What is diffusion?
الإجابة
Net movement from higher to lower concentration. It is passive and continues until dynamic equilibrium is reached.
البطاقة ٢٠٠
السؤال
What happens to an animal cell in a strongly hypotonic solution?
الإجابة
Water enters and the cell swells. Without a cell wall, it may burst.
البطاقة ٢٠١
السؤال
What happens during interphase?
الإجابة
The cell grows, performs normal functions, and copies its DNA. Interphase precedes mitotic division.
البطاقة ٢٠٢
السؤال
What is the result of mitosis followed by cytokinesis?
الإجابة
Two genetically similar daughter cells. Chromosome number is normally preserved.
البطاقة ٢٠٣
السؤال
What is osmosis?
الإجابة
Diffusion of water across a selectively permeable membrane. Water moves toward the side with more nonpenetrating solute.
البطاقة ٢٠٤
السؤال
What happens to an animal cell in a hypertonic solution?
الإجابة
Water leaves and the cell shrinks. The external solution has a higher effective solute concentration.
البطاقة ٢٠٥
السؤال
Why are cells generally small?
الإجابة
A high surface-area-to-volume ratio supports efficient exchange. Volume grows faster than surface area as a cell enlarges.
البطاقة ٢٠٦
السؤال
What is cytokinesis?
الإجابة
Division of the cytoplasm. It separates one cell into two after nuclear division.
البطاقة ٢٠٧
السؤال
How does active transport differ from passive transport?
الإجابة
It uses energy to move substances against a gradient. Passive transport moves down a gradient without direct energy input.
البطاقة ٢٠٨
السؤال
What happens to an animal cell in an isotonic solution?
الإجابة
There is no net water movement. Water still crosses in both directions at equal rates.
البطاقة ٢٠٩
السؤال
Which structures are typical of plant cells but not animal cells?
الإجابة
A cellulose cell wall, chloroplasts, and a large central vacuole. Both cell types have membranes, nuclei, and mitochondria.
البطاقة ٢١٠
السؤال
How do cells contribute to a multicellular organism's organization?
الإجابة
Specialized cells form tissues, tissues form organs, and organs form systems. Division of labor supports complex functions.
البطاقة ٢١١
السؤال
What is DNA's primary biological role?
الإجابة
Storing hereditary information. Its nucleotide sequence contains instructions used to build functional RNA and proteins.
البطاقة ٢١٢
السؤال
What are the three parts of a DNA nucleotide?
الإجابة
A deoxyribose sugar, a phosphate group, and a nitrogenous base. Nucleotides link to form each strand.
البطاقة ٢١٣
السؤال
Which bases pair in double-stranded DNA?
الإجابة
Adenine with thymine, and cytosine with guanine. Hydrogen bonds hold complementary strands together.
البطاقة ٢١٤
السؤال
How does RNA differ from DNA?
الإجابة
RNA usually has ribose, uses uracil instead of thymine, and is usually single-stranded. Several RNA types help express genes.
البطاقة ٢١٥
السؤال
What is a gene?
الإجابة
A DNA sequence that contributes to a functional product. The product may be a protein or a functional RNA.
البطاقة ٢١٦
السؤال
What is a chromosome?
الإجابة
A long DNA molecule packaged with proteins. It contains many genes and other sequences.
البطاقة ٢١٧
السؤال
What is DNA replication?
الإجابة
Copying DNA before cell division. Each new DNA molecule contains one old strand and one newly made strand.
البطاقة ٢١٨
السؤال
What is the usual flow of information from a protein-coding gene?
الإجابة
DNA to RNA to protein. Transcription makes RNA; translation builds the polypeptide.
البطاقة ٢١٩
السؤال
What happens during transcription?
الإجابة
RNA is synthesized from a DNA template. For a protein-coding gene, that RNA functions as or is processed into messenger RNA.
البطاقة ٢٢٠
السؤال
What does messenger RNA carry?
الإجابة
A copy of coding information from DNA to a ribosome. Its codons specify the amino-acid sequence.
البطاقة ٢٢١
السؤال
What is a codon?
الإجابة
A three-nucleotide sequence in mRNA. Most codons specify an amino acid; some signal start or stop.
البطاقة ٢٢٢
السؤال
What is the usual role of the AUG codon?
الإجابة
It starts translation and specifies methionine. The ribosome uses it to establish the reading frame.
البطاقة ٢٢٣
السؤال
What happens during translation?
الإجابة
A ribosome reads mRNA and joins amino acids into a polypeptide. Transfer RNAs match codons with amino acids.
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البطاقة ٢٢٤
السؤال
What is transfer RNA's role in protein synthesis?
الإجابة
It carries an amino acid and matches its anticodon to an mRNA codon. This places the correct amino acid in sequence.
البطاقة ٢٢٥
السؤال
What is an anticodon?
الإجابة
A three-base sequence on tRNA complementary to an mRNA codon. Pairing helps decode the message.
البطاقة ٢٢٦
السؤال
What is a mutation?
الإجابة
A change in a DNA sequence. Its effect may be harmful, neutral, or beneficial depending on location and context.
البطاقة ٢٢٧
السؤال
Why can a one-base insertion in a coding sequence have a large effect?
الإجابة
It can shift the reading frame. Every downstream codon may change until a stop signal appears.
البطاقة ٢٢٨
السؤال
Why can changing one amino acid alter a protein's function?
الإجابة
Amino-acid sequence helps determine folding and shape. Shape controls many protein interactions.
البطاقة ٢٢٩
السؤال
What is ribosomal RNA's role in protein synthesis?
الإجابة
It forms the structural and catalytic core of ribosomes. Ribosomal RNA helps align translation components and catalyzes peptide-bond formation.
البطاقة ٢٣٠
السؤال
Why can different cell types contain the same DNA but perform different jobs?
الإجابة
They express different sets of genes. Different proteins give cells different structures and functions.
البطاقة ٢٣١
السؤال
Which mutation can be passed to offspring?
الإجابة
A mutation present in a gamete-forming lineage. A mutation limited to ordinary body cells is not inherited through reproduction.
البطاقة ٢٣٢
السؤال
What is an allele?
الإجابة
An alternative version of a gene. Diploid individuals usually carry two alleles for each autosomal gene.
البطاقة ٢٣٣
السؤال
What is genotype?
الإجابة
An organism's allele combination for a gene or set of genes. Genotype contributes to phenotype.
البطاقة ٢٣٤
السؤال
What does homozygous mean?
الإجابة
Having two identical alleles for a gene. Examples include AA and aa.
البطاقة ٢٣٥
السؤال
What makes an allele dominant in a simple Mendelian trait?
الإجابة
One copy is enough for its phenotype to appear in a heterozygote. Dominant does not mean common or beneficial.
البطاقة ٢٣٦
السؤال
What does Mendel's law of segregation describe?
الإجابة
The two alleles for a gene separate during gamete formation. Each gamete receives one allele.
البطاقة ٢٣٧
السؤال
What is phenotype?
الإجابة
An observable trait or characteristic. It can reflect genotype, environment, and their interaction.
البطاقة ٢٣٨
السؤال
What does heterozygous mean?
الإجابة
Having two different alleles for a gene. An example is Aa.
البطاقة ٢٣٩
السؤال
When does a recessive phenotype usually appear in a simple autosomal trait?
الإجابة
When both alleles are recessive. A heterozygote carries the allele without showing that phenotype.
البطاقة ٢٤٠
السؤال
When does independent assortment apply most clearly?
الإجابة
When genes are on different chromosomes or far apart on the same chromosome. Their allele pairs enter gametes independently.
البطاقة ٢٤١
السؤال
What does a Punnett square predict?
الإجابة
Expected offspring genotype probabilities from specified parental gametes. It does not guarantee outcomes in a small family.
البطاقة ٢٤٢
السؤال
For Aa × Aa, what is the chance of an aa offspring?
الإجابة
One fourth, or 25%. The genotype ratio is expected to be 1 AA : 2 Aa : 1 aa.
البطاقة ٢٤٣
السؤال
For Aa × Aa with complete dominance, what phenotypic ratio is expected?
الإجابة
Three dominant-phenotype offspring to one recessive-phenotype offspring. This is a probability across many offspring.
البطاقة ٢٤٤
السؤال
How can a test cross reveal the genotype behind a dominant phenotype?
الإجابة
Cross the individual with a homozygous recessive partner. Recessive offspring show that the unknown parent carried a recessive allele.
البطاقة ٢٤٥
السؤال
What happens in incomplete dominance?
الإجابة
A heterozygote has an intermediate phenotype. Neither allele fully masks the other.
البطاقة ٢٤٦
السؤال
How is the probability of two independent genetic events both occurring found?
الإجابة
Multiply their individual probabilities. This is the product rule.
البطاقة ٢٤٧
السؤال
What does a pedigree show?
الإجابة
How a trait appears across generations of a family. Its pattern can suggest a mode of inheritance.
البطاقة ٢٤٨
السؤال
Why can two parents have offspring ratios that differ from a Punnett-square expectation?
الإجابة
Each fertilization is a chance event. Expected ratios become more apparent with larger numbers of offspring.
البطاقة ٢٤٩
السؤال
What happens in codominance?
الإجابة
Both alleles are distinctly expressed in a heterozygote. The AB blood type is a common example.
البطاقة ٢٥٠
السؤال
What are major roles of carbohydrates?
الإجابة
Providing quick energy, storing energy, and forming some structures. Monosaccharides are their basic building blocks.
البطاقة ٢٥١
السؤال
What is a monomer?
الإجابة
A small building block that can join with others to form a larger molecule. Glucose, amino acids, and nucleotides are examples in different classes.
البطاقة ٢٥٢
السؤال
What happens in a dehydration-synthesis reaction?
الإجابة
Monomers join while water is removed. The reaction builds a larger biological molecule.
البطاقة ٢٥٣
السؤال
What does an enzyme do?
الإجابة
It lowers activation energy and speeds a reaction without being consumed. Its shape helps it bind specific substrates.
البطاقة ٢٥٤
السؤال
What are major roles of lipids?
الإجابة
Long-term energy storage, membranes, insulation, and signaling. Lipids are mostly nonpolar and do not mix well with water.
البطاقة ٢٥٥
السؤال
What does it mean for a protein to denature?
الإجابة
Its normal shape is disrupted. Heat, extreme pH, or chemicals can reduce its function.
البطاقة ٢٥٦
السؤال
What happens during hydrolysis?
الإجابة
Water is used to split a larger molecule into smaller units. Digestion often uses hydrolysis reactions.
البطاقة ٢٥٧
السؤال
Why do phospholipids form bilayers in water?
الإجابة
Their hydrophilic heads interact with water while hydrophobic tails turn inward. This arrangement forms cell-membrane structure.
البطاقة ٢٥٨
السؤال
What are proteins built from?
الإجابة
Amino acids linked by peptide bonds. Their folded shapes support enzymes, transport, signaling, structure, and movement.
البطاقة ٢٥٩
السؤال
How do starch and glycogen compare?
الإجابة
Both store glucose; plants use starch and animals use glycogen. Their branching patterns differ.
البطاقة ٢٦٠
السؤال
How do saturated and unsaturated fatty acids differ?
الإجابة
Saturated fatty acids lack carbon-carbon double bonds; unsaturated ones have one or more. Double bonds often introduce bends.
البطاقة ٢٦١
السؤال
What immediate energy-carrying molecule powers many cell processes?
الإجابة
ATP. Energy released from nutrients can be transferred into ATP's phosphate bonds.
البطاقة ٢٦٢
السؤال
What are nucleic acids built from?
الإجابة
Nucleotides. DNA stores hereditary information, while RNA performs several roles in gene expression.
البطاقة ٢٦٣
السؤال
Which elements are common in all four major biological macromolecule classes?
الإجابة
Carbon, hydrogen, and oxygen. Nitrogen and phosphorus occur prominently in some classes.
البطاقة ٢٦٤
السؤال
Why is three-dimensional shape important for macromolecules?
الإجابة
Shape determines many interactions and functions. A changed shape can prevent a molecule from binding its target.
البطاقة ٢٦٥
السؤال
What are triglycerides built from?
الإجابة
One glycerol molecule and three fatty acids. They join through ester bonds to form a common energy-storage lipid.
البطاقة ٢٦٦
السؤال
What is a pathogen?
الإجابة
An agent capable of causing disease. Not every microorganism is pathogenic.
البطاقة ٢٦٧
السؤال
What type of cell is a bacterium?
الإجابة
A prokaryotic cell. Bacteria usually reproduce by binary fission.
البطاقة ٢٦٨
السؤال
What cell type do fungi have?
الإجابة
Eukaryotic cells. Some fungi are unicellular yeasts, while others form multicellular filaments.
البطاقة ٢٦٩
السؤال
What does disease transmission describe?
الإجابة
How an infectious agent moves to a susceptible host. Routes include contact, droplets, airborne spread, food, water, and vectors.
البطاقة ٢٧٠
السؤال
What is a biological vector?
الإجابة
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.
البطاقة ٢٧١
السؤال
Why are viruses dependent on host cells?
الإجابة
They lack the complete machinery for reproduction and metabolism. They use host components to make new virus particles.
البطاقة ٢٧٢
السؤال
What is a protist?
الإجابة
A diverse eukaryote that is not classified as an animal, plant, or fungus. Some protists cause disease, while many do not.
البطاقة ٢٧٣
السؤال
Why do antibiotics not treat viral infections?
الإجابة
They target bacterial structures or processes that viruses lack. Antiviral drugs use different targets.
البطاقة ٢٧٤
السؤال
How can normal microbiota protect a host?
الإجابة
They occupy space and use resources that pathogens might otherwise exploit. Some also support digestion or immune development.
البطاقة ٢٧٥
السؤال
How does sterilization differ from disinfection?
الإجابة
Sterilization destroys or removes all microbial life, including resistant forms; disinfection reduces pathogens on objects. The required method depends on use.
البطاقة ٢٧٦
السؤال
How do infection and disease differ?
الإجابة
Infection means an agent is established in a host; disease means normal function is impaired and signs or symptoms occur. Infection may be asymptomatic.
البطاقة ٢٧٧
السؤال
How can breaking a transmission route reduce infectious disease?
الإجابة
It interrupts the chain connecting a source with a susceptible host. Hand hygiene, clean water, ventilation, and vector control target different links.
البطاقة ٢٧٨
السؤال
What is an atom?
الإجابة
The smallest unit of an element that retains that element's chemical identity. Atoms contain a nucleus surrounded by electrons.
البطاقة ٢٧٩
السؤال
What charge and location does an electron have?
الإجابة
Negative charge in the electron cloud around the nucleus. Electrons drive most chemical bonding.
البطاقة ٢٨٠
السؤال
Why are valence electrons important?
الإجابة
They participate most directly in bonding and reactions. Their arrangement helps predict chemical behavior.
البطاقة ٢٨١
السؤال
What do elements in the same periodic-table group often share?
الإجابة
Similar valence-electron patterns and chemical properties. A group is a vertical column.
البطاقة ٢٨٢
السؤال
What is an ion?
الإجابة
An atom or group of atoms with a net electric charge. Its total numbers of protons and electrons are unequal.
البطاقة ٢٨٣
السؤال
What charge and location does a proton have?
الإجابة
Positive charge in the nucleus. The number of protons determines the element.
البطاقة ٢٨٤
السؤال
What does an element's atomic number equal?
الإجابة
Its number of protons. A neutral atom has the same number of electrons.
البطاقة ٢٨٥
السؤال
How does a neutral atom form a cation?
الإجابة
By losing one or more electrons. It has more protons than electrons and a positive charge.
البطاقة ٢٨٦
السؤال
An atom has 8 protons. How many electrons does it have if it is neutral?
الإجابة
Eight electrons. Neutral atoms have equal positive and negative charges.
البطاقة ٢٨٧
السؤال
What charge and location does a neutron have?
الإجابة
No electric charge, in the nucleus. Neutron number can vary among isotopes of an element.
البطاقة ٢٨٨
السؤال
What does mass number equal?
الإجابة
Protons plus neutrons in one atom. It is a whole number for a specific isotope.
البطاقة ٢٨٩
السؤال
How does a neutral atom form an anion?
الإجابة
By gaining one or more electrons. It has more electrons than protons and a negative charge.
البطاقة ٢٩٠
السؤال
What does a period represent on the periodic table?
الإجابة
A horizontal row. Moving across a period changes proton number one element at a time.
البطاقة ٢٩١
السؤال
What are isotopes?
الإجابة
Atoms of the same element with different numbers of neutrons. They have the same atomic number but different mass numbers.
البطاقة ٢٩٢
السؤال
What is matter?
الإجابة
Anything that has mass and occupies space. Solids, liquids, gases, and plasma are forms of matter.
البطاقة ٢٩٣
السؤال
What distinguishes a solid from a liquid or gas?
الإجابة
A solid has a definite shape and volume. Its particles vibrate around relatively fixed positions.
البطاقة ٢٩٤
السؤال
What is a physical change?
الإجابة
A change in form or state without changing chemical identity. Melting and cutting are examples.
البطاقة ٢٩٥
السؤال
What is a physical property?
الإجابة
A characteristic observed without changing a substance's identity. Density, color, and melting point are examples.
البطاقة ٢٩٦
السؤال
How does an element differ from a compound?
الإجابة
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.
البطاقة ٢٩٧
السؤال
What distinguishes a liquid?
الإجابة
It has a definite volume but takes the shape of its container. Its particles remain close while moving past one another.
البطاقة ٢٩٨
السؤال
What is a chemical change?
الإجابة
A process that forms one or more substances with new chemical identities. Bond rearrangement occurs.
البطاقة ٢٩٩
السؤال
What is a chemical property?
الإجابة
A substance's ability to undergo a particular chemical change. Flammability and reactivity with acid are examples.
البطاقة ٣٠٠
السؤال
Which phase changes connect solids and liquids?
الإجابة
Melting changes a solid to a liquid; freezing changes a liquid to a solid. These are opposite physical changes.
البطاقة ٣٠١
السؤال
How does a pure substance differ from a mixture?
الإجابة
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.
البطاقة ٣٠٢
السؤال
What distinguishes a gas?
الإجابة
It has neither a definite shape nor a definite volume. It expands to fill its container.
البطاقة ٣٠٣
السؤال
What is the formula for density?
الإجابة
Density = mass ÷ volume. Density is an intensive property.
البطاقة ٣٠٤
السؤال
Which phase changes connect liquids and gases?
الإجابة
Vaporization changes a liquid to a gas; condensation changes a gas to a liquid. Evaporation is vaporization at a liquid's surface.
البطاقة ٣٠٥
السؤال
What is a mixture?
الإجابة
Two or more substances physically combined in variable proportions. Its components retain their chemical identities.
البطاقة ٣٠٦
السؤال
How do intensive and extensive properties differ?
الإجابة
Intensive properties do not depend on sample amount; extensive properties do. Density and temperature are intensive, while mass and volume are extensive.
البطاقة ٣٠٧
السؤال
A 20 g sample occupies 5 mL. What is its density?
الإجابة
4 g/mL. Divide 20 g by 5 mL.
البطاقة ٣٠٨
السؤال
Which phase changes connect solids and gases directly?
الإجابة
Sublimation changes a solid to a gas; deposition changes a gas to a solid. Neither transition passes through the liquid state.
البطاقة ٣٠٩
السؤال
How do homogeneous and heterogeneous mixtures differ?
الإجابة
A homogeneous mixture is uniform throughout; a heterogeneous mixture is not. A solution is homogeneous.
البطاقة ٣١٠
السؤال
Where are reactants and products written in a chemical equation?
الإجابة
Reactants are on the left; products are on the right. The arrow shows the direction represented.
البطاقة ٣١١
السؤال
Why must a chemical equation be balanced?
الإجابة
Atoms are conserved in ordinary chemical reactions. Each element must have the same atom count on both sides.
البطاقة ٣١٢
السؤال
What does a coefficient in a chemical equation change?
الإجابة
The number of whole particles or moles represented. It multiplies every atom in the following formula.
البطاقة ٣١٣
السؤال
Why should subscripts not be changed when balancing an equation?
الإجابة
Changing a subscript changes the substance's identity. Balancing changes coefficients only.
البطاقة ٣١٤
السؤال
What coefficients balance H₂ + O₂ → H₂O?
الإجابة
2, 1, 2: 2H₂ + O₂ → 2H₂O. Both sides then contain four hydrogen atoms and two oxygen atoms.
البطاقة ٣١٥
السؤال
What pattern defines a synthesis reaction?
الإجابة
Two or more reactants form a more complex product. A general pattern is A + B → AB.
البطاقة ٣١٦
السؤال
What are typical products when a hydrocarbon burns completely in oxygen?
الإجابة
Carbon dioxide and water. Incomplete combustion can produce carbon monoxide or carbon.
البطاقة ٣١٧
السؤال
What is the net ionic equation for a typical strong acid–strong base neutralization?
الإجابة
H⁺(aq) + OH⁻(aq) → H₂O(l). The remaining ions are spectators and do not appear in the net ionic equation.
البطاقة ٣١٨
السؤال
What is a precipitate?
الإجابة
An insoluble solid that forms from substances in solution. Its appearance can signal a chemical reaction.
البطاقة ٣١٩
السؤال
What pattern defines a decomposition reaction?
الإجابة
One compound breaks into simpler products. A general pattern is AB → A + B.
البطاقة ٣٢٠
السؤال
What is an exothermic reaction?
الإجابة
A reaction that releases heat to the surroundings. The surroundings often warm.
البطاقة ٣٢١
السؤال
What occurs in an oxidation-reduction reaction?
الإجابة
Electrons transfer or atoms change oxidation state. Oxidation is electron loss; reduction is electron gain.
البطاقة ٣٢٢
السؤال
What is activation energy?
الإجابة
The minimum energy barrier reactants must overcome to react. Catalysts lower this barrier.
البطاقة ٣٢٣
السؤال
Which observations can provide evidence of a chemical reaction?
الإجابة
Gas formation, a precipitate, sustained color change, light, or temperature change. No single sign proves a reaction without context.
البطاقة ٣٢٤
السؤال
What is an endothermic reaction?
الإجابة
A reaction that absorbs heat from the surroundings. The surroundings may cool.
البطاقة ٣٢٥
السؤال
Why does raising temperature usually speed a reaction?
الإجابة
Particles collide more often and with greater energy. More collisions overcome activation energy.
البطاقة ٣٢٦
السؤال
Why can higher reactant concentration increase reaction rate?
الإجابة
More reactant particles occupy a given volume. This raises collision frequency.
البطاقة ٣٢٧
السؤال
Why does powdered solid often react faster than one large piece?
الإجابة
Powder exposes more surface area. More particles are available for collisions.
البطاقة ٣٢٨
السؤال
How does a catalyst speed a reaction?
الإجابة
It provides a pathway with lower activation energy. The catalyst is regenerated rather than consumed overall.
البطاقة ٣٢٩
السؤال
How can increasing pressure affect a reaction between gases?
الإجابة
It can increase rate by bringing gas particles closer together. Collision frequency rises when volume falls.
البطاقة ٣٣٠
السؤال
What does a reaction inhibitor do?
الإجابة
It slows a reaction. It may block a pathway, interfere with a catalyst, or remove reactive intermediates.
البطاقة ٣٣١
السؤال
Why can very high temperature slow an enzyme-catalyzed reaction?
الإجابة
The enzyme can denature and lose its active shape. Moderate warming helps only within the enzyme's stable range.
البطاقة ٣٣٢
السؤال
What is dynamic equilibrium?
الإجابة
Forward and reverse reactions continue at equal rates. Concentrations remain constant even though particles still react.
البطاقة ٣٣٣
السؤال
Does a catalyst change the final equilibrium amounts?
الإجابة
No. It speeds forward and reverse reactions, so equilibrium is reached sooner without changing its position.
البطاقة ٣٣٤
السؤال
At equilibrium, what usually happens when the concentration of a dissolved or gaseous reactant increases?
الإجابة
The system shifts toward consuming some added reactant. It forms more product until a new equilibrium is reached.
البطاقة ٣٣٥
السؤال
What is a solution?
الإجابة
A homogeneous mixture. Its components are uniformly distributed at the molecular or ionic level.
البطاقة ٣٣٦
السؤال
How do solute and solvent differ?
الإجابة
The solute is dissolved; the solvent is the dissolving medium. The solvent is often present in greater amount.
البطاقة ٣٣٧
السؤال
What does aqueous mean in chemistry?
الإجابة
Dissolved in water. The symbol (aq) marks an aqueous species in an equation.
البطاقة ٣٣٨
السؤال
What does concentration describe?
الإجابة
The amount of solute in a given amount of solution or solvent. Different units express it in different ways.
البطاقة ٣٣٩
السؤال
What is molarity?
الإجابة
Moles of solute per liter of solution. Its unit is mol/L, written M.
البطاقة ٣٤٠
السؤال
What is the molarity of 0.50 mol solute in 2.0 L of solution?
الإجابة
0.25 M. Divide 0.50 mol by 2.0 L.
البطاقة ٣٤١
السؤال
What stays constant when water is added to dilute a solution without reaction?
الإجابة
The moles of solute. Volume increases and concentration decreases.
البطاقة ٣٤٢
السؤال
Which equation relates concentration and volume before and after a dilution?
الإجابة
M₁V₁ = M₂V₂. It follows from conserving the amount of solute.
البطاقة ٣٤٣
السؤال
What is solubility?
الإجابة
The maximum concentration of a solute that can be achieved in a solution at equilibrium under specified conditions. Temperature and the substances involved matter.
البطاقة ٣٤٤
السؤال
What is a saturated solution?
الإجابة
A solution holding the maximum dissolved solute at those conditions. Extra solute remains undissolved at equilibrium.
البطاقة ٣٤٥
السؤال
What is an electrolyte?
الإجابة
A substance that produces mobile ions in solution and conducts electricity. Soluble ionic compounds are common examples.
البطاقة ٣٤٦
السؤال
What does 'like dissolves like' predict?
الإجابة
Substances with similar polarity tend to mix well. Polar solvents favor polar or ionic solutes; nonpolar solvents favor nonpolar solutes.
البطاقة ٣٤٧
السؤال
Does heating always increase solubility?
الإجابة
No. Many solids become more soluble in water, but gases usually become less soluble as temperature rises.
البطاقة ٣٤٨
السؤال
What is an unsaturated solution?
الإجابة
A solution that can dissolve more solute at the stated conditions. It is below the solubility limit.
البطاقة ٣٤٩
السؤال
What does a Brønsted-Lowry acid donate?
الإجابة
A proton, H⁺. In water, acid behavior increases hydronium-ion concentration.
البطاقة ٣٥٠
السؤال
What does pH describe?
الإجابة
The hydronium-ion concentration on a logarithmic scale. Lower pH means higher hydronium concentration.
البطاقة ٣٥١
السؤال
At 25 °C, what pH range is acidic?
الإجابة
Below 7. A neutral aqueous solution is pH 7 at this temperature.
البطاقة ٣٥٢
السؤال
How does hydronium concentration change when pH drops by 1 unit?
الإجابة
It increases tenfold. The pH scale is logarithmic.
البطاقة ٣٥٣
السؤال
What does a Brønsted-Lowry base accept?
الإجابة
A proton, H⁺. Many bases in water also increase hydroxide-ion concentration.
البطاقة ٣٥٤
السؤال
At 25 °C, what is the relationship between pH and pOH?
الإجابة
pH + pOH = 14. pOH is the negative base-10 logarithm of hydroxide-ion concentration; this relation applies to aqueous solutions at 25 °C.
البطاقة ٣٥٥
السؤال
At 25 °C, what pH range is basic?
الإجابة
Above 7. Basic solutions have less hydronium and more hydroxide than neutral water.
البطاقة ٣٥٦
السؤال
What are typical products of a strong acid reacting with a strong base?
الإجابة
Water and an ionic salt. Hydrogen ions and hydroxide ions combine to form water.
البطاقة ٣٥٧
السؤال
What does strong mean for an acid or base?
الإجابة
It produces its characteristic ions essentially completely in water. Strong acids ionize; soluble ionic strong bases dissociate. Strength is separate from concentration.
البطاقة ٣٥٨
السؤال
What does a buffer do?
الإجابة
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⁻.
البطاقة ٣٥٩
السؤال
How does an acid-base indicator work?
الإجابة
Its color depends on pH. The change occurs over a characteristic pH range.
البطاقة ٣٦٠
السؤال
A solution has pH 9 at 25 °C. What is its pOH?
الإجابة
5. Subtract the pH from 14.
البطاقة ٣٦١
السؤال
How does a concentrated weak acid differ from a dilute strong acid?
الإجابة
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.
البطاقة ٣٦٢
السؤال
What is the SI base unit of length?
الإجابة
The meter (m). Centimeters and millimeters are decimal subdivisions of a meter.
البطاقة ٣٦٣
السؤال
Which tool directly measures mass in a laboratory?
الإجابة
A balance. A spring scale measures force, often reported as weight.
البطاقة ٣٦٤
السؤال
What is the SI base unit of mass?
الإجابة
The kilogram (kg). Laboratory mass is also commonly reported in grams.
البطاقة ٣٦٥
السؤال
A student needs to measure about 35 mL of liquid and can choose a beaker or graduated cylinder. Which should they use?
الإجابة
A graduated cylinder. Read the scale at eye level.
البطاقة ٣٦٦
السؤال
What is the SI base unit of time?
الإجابة
The second (s). Minutes and hours are accepted for many everyday uses.
البطاقة ٣٦٧
السؤال
Where should the volume of a clear water-based liquid be read in a graduated cylinder?
الإجابة
At the bottom of the meniscus. Keep your eye level with the liquid surface.
البطاقة ٣٦٨
السؤال
What is the SI base unit of thermodynamic temperature?
الإجابة
The kelvin (K). Degrees Celsius are widely used for laboratory and body temperatures.
البطاقة ٣٦٩
السؤال
Which tool measures temperature?
الإجابة
A thermometer. Its range and resolution should match the task.
البطاقة ٣٧٠
السؤال
What factor does the metric prefix kilo- represent?
الإجابة
One thousand, or 10³. One kilometer equals 1,000 meters.
البطاقة ٣٧١
السؤال
A ruler's smallest marking is 1 mm. To what place should a careful analog reading usually be estimated?
الإجابة
One place beyond the smallest marking, when the scale allows it. The final digit is uncertain.
البطاقة ٣٧٢
السؤال
What is measurement accuracy?
الإجابة
Closeness to an accepted or true value. A systematic error can make precise measurements inaccurate.
البطاقة ٣٧٣
السؤال
How do mass and weight differ?
الإجابة
Mass is the amount of matter; weight is gravitational force on that mass. Mass stays constant when gravity changes, but weight does not.
البطاقة ٣٧٤
السؤال
What factor does the metric prefix milli- represent?
الإجابة
One thousandth, or 10⁻³. One milliliter is 0.001 liter.
البطاقة ٣٧٥
السؤال
How can the volume of an irregular solid be measured with water?
الإجابة
Use water displacement. Subtract the initial water volume from the final volume after submerging the object.
البطاقة ٣٧٦
السؤال
What is measurement precision?
الإجابة
Closeness of repeated measurements to one another. Precise results can still be consistently wrong.
البطاقة ٣٧٧
السؤال
What is an instrument's resolution?
الإجابة
The smallest change it can meaningfully display or distinguish. Higher resolution does not automatically guarantee accuracy.
البطاقة ٣٧٨
السؤال
How many centimeters are in 2.5 meters?
الإجابة
2.5 × 10² cm (250 cm). Multiply meters by the exact conversion factor 100 cm/m.
البطاقة ٣٧٩
السؤال
Why must a numerical measurement include a unit?
الإجابة
The unit identifies the quantity's scale. A bare number is ambiguous and cannot be compared reliably.
البطاقة ٣٨٠
السؤال
What is a scientific observation?
الإجابة
Information recorded with senses or instruments. It should be distinguished from an explanation of what was observed.
البطاقة ٣٨١
السؤال
What makes a hypothesis scientifically useful?
الإجابة
It is testable and falsifiable. Evidence must be able to count against it.
البطاقة ٣٨٢
السؤال
What is a scientific theory?
الإجابة
A broad, well-supported explanation of natural phenomena. It is not a casual guess and can be revised with new evidence.
البطاقة ٣٨٣
السؤال
Which claim is falsifiable: 'No possible observation could count against this treatment's effectiveness' or 'This treatment lowers mean temperature within one hour'?
الإجابة
The claim that the treatment lowers mean temperature within one hour. An observation could count against it, so evidence can test it.
البطاقة ٣٨٤
السؤال
What is an inference?
الإجابة
A logical interpretation based on observations and prior knowledge. It goes beyond the raw measurement.
البطاقة ٣٨٥
السؤال
How does a prediction relate to a hypothesis?
الإجابة
It states an expected result if the hypothesis is correct. Experiments compare observed results with that expectation.
البطاقة ٣٨٦
السؤال
How does a scientific law differ from a scientific theory?
الإجابة
A law describes a consistent pattern; a theory explains how or why patterns occur. One does not mature into the other.
البطاقة ٣٨٧
السؤال
What does reliability mean for a measurement or procedure?
الإجابة
It produces consistent results under the same conditions. Repetition helps assess reliability.
البطاقة ٣٨٨
السؤال
What does a correlation show?
الإجابة
Two variables change together in a patterned way. Correlation alone does not establish that one causes the other.
البطاقة ٣٨٩
السؤال
What is bias in scientific work?
الإجابة
A systematic influence that pushes observations, selection, or interpretation in one direction. Good design tries to prevent or measure it.
البطاقة ٣٩٠
السؤال
What is the purpose of scientific peer review?
الإجابة
Independent experts evaluate methods, reasoning, and reporting before publication. It improves scrutiny but does not guarantee truth.
البطاقة ٣٩١
السؤال
What does validity ask about a study or measurement?
الإجابة
Whether it measures or tests what it claims to measure or test. Consistency alone does not ensure validity.
البطاقة ٣٩٢
السؤال
What evidence most strengthens a causal claim?
الإجابة
A well-controlled experiment that manipulates the suspected cause. Random assignment reduces confounding, while independent replication tests whether the result holds with new data.
البطاقة ٣٩٣
السؤال
What is a primary scientific source?
الإجابة
A report of original methods, data, and results. A review article synthesizes many primary studies.
البطاقة ٣٩٤
السؤال
How should an unexpected outlier be handled?
الإجابة
Investigate and report it rather than deleting it automatically. Exclusion needs a documented scientific reason.
البطاقة ٣٩٥
السؤال
What is a confounding variable?
الإجابة
An outside factor related to both the suspected cause and the outcome. It can create a misleading association.
البطاقة ٣٩٦
السؤال
Why should a sample represent the population of interest?
الإجابة
Results generalize poorly when important groups are missing or overrepresented. Sampling method matters as much as size.
البطاقة ٣٩٧
السؤال
What is a scientific model?
الإجابة
A simplified representation used to explain or predict a system. A model is useful within its assumptions and limits.
البطاقة ٣٩٨
السؤال
Why should measurements report uncertainty or reasonable precision?
الإجابة
Every measurement has limits. Reporting more digits than the method supports creates false precision.
البطاقة ٣٩٩
السؤال
If results match a prediction once, what is the safest conclusion?
الإجابة
The results support the hypothesis under those conditions. One result does not prove the hypothesis in every setting.
البطاقة ٤٠٠
السؤال
What is a direct relationship between two variables?
الإجابة
As one increases, the other tends to increase; as one decreases, the other tends to decrease. The relationship need not be perfectly linear.
البطاقة ٤٠١
السؤال
Which variable is usually placed on the x-axis of an experimental graph?
الإجابة
The independent variable. It is the factor selected or changed by the investigator.
البطاقة ٤٠٢
السؤال
What does the slope of a straight-line graph represent?
الإجابة
Change in y divided by change in x. It is the response rate per unit change in the other variable.
البطاقة ٤٠٣
السؤال
A line rises 12 units in y while x rises 3 units. What is its slope?
الإجابة
4 units of y per unit of x. Divide 12 by 3.
البطاقة ٤٠٤
السؤال
What is an inverse relationship?
الإجابة
As one variable increases, the other tends to decrease. Their product is constant only in a strictly inverse proportion.
البطاقة ٤٠٥
السؤال
Which variable is usually placed on the y-axis of an experimental graph?
الإجابة
The dependent variable. It is the measured response.
البطاقة ٤٠٦
السؤال
What does a plateau on a response graph indicate?
الإجابة
The measured response has stopped changing much despite further x increases. A limiting factor may have been reached.
البطاقة ٤٠٧
السؤال
What is interpolation?
الإجابة
Estimating a value within the range of measured data. It is generally safer than extrapolating beyond that range.
البطاقة ٤٠٨
السؤال
What pattern suggests no relationship between two plotted variables?
الإجابة
The response shows no consistent change as the other variable changes. Points may scatter without a trend.
البطاقة ٤٠٩
السؤال
Before comparing values in a data table, what should you check?
الإجابة
Headings, units, and conditions. Numbers from different measures or scales cannot be compared directly.
البطاقة ٤١٠
السؤال
If 3 samples require 12 mL total, how much is needed for 5 equal samples?
الإجابة
20 mL. The rate is 4 mL per sample, so multiply by 5.
البطاقة ٤١١
السؤال
How is the arithmetic mean calculated?
الإجابة
Add all values and divide by the number of values. A large outlier can shift the mean.
البطاقة ٤١٢
السؤال
Why is extrapolation uncertain?
الإجابة
It assumes the observed trend continues outside measured conditions. The relationship may change beyond the data range.
البطاقة ٤١٣
السؤال
A culture grows from 20 to 50 cells in 6 hours. What is the average growth rate?
الإجابة
5 cells per hour. The change is 30 cells divided by 6 hours.
البطاقة ٤١٤
السؤال
A measurement rises from 40 to 50. What is the percent increase?
الإجابة
25%. The increase is 10, and 10 ÷ 40 × 100 = 25%.
البطاقة ٤١٥
السؤال
When can the median describe a typical value better than the mean?
الإجابة
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.
البطاقة ٤١٦
السؤال
How do quantitative and qualitative data differ?
الإجابة
Quantitative data are numerical; qualitative data describe categories or qualities. Both can answer scientific questions.
البطاقة ٤١٧
السؤال
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?
الإجابة
6. The observed rate is 2 response units per dose unit, so interpolation at dose 3 gives 6.
البطاقة ٤١٨
السؤال
How can a graph reveal a nonlinear relationship?
الإجابة
The points follow a curve rather than a straight line. The rate of change varies across the x-range.
البطاقة ٤١٩
السؤال
What is the range of a data set?
الإجابة
Maximum minus minimum. It describes total spread but ignores the distribution between the endpoints.
البطاقة ٤٢٠
السؤال
What makes a scientific research question testable?
الإجابة
It identifies measurable variables or observable outcomes. The needed data must be obtainable.
البطاقة ٤٢١
السؤال
In an experiment, what is the independent variable?
الإجابة
The factor deliberately changed or assigned by the investigator. In a simple one-factor experiment, changing one independent variable helps isolate its effect.
البطاقة ٤٢٢
السؤال
What should a hypothesis connect?
الإجابة
A proposed explanation with a measurable outcome. It should lead to a prediction that evidence can challenge.
البطاقة ٤٢٣
السؤال
What is a controlled variable, or constant?
الإجابة
A condition kept the same across groups. Holding it constant prevents it from explaining outcome differences.
البطاقة ٤٢٤
السؤال
What is the purpose of a control group?
الإجابة
It provides a comparison without the experimental treatment. Differences can then be attributed more confidently to the treatment.
البطاقة ٤٢٥
السؤال
In an experiment, what is the dependent variable?
الإجابة
The measured response. It may change because of the independent variable.
البطاقة ٤٢٦
السؤال
What form can a useful experimental prediction take?
الإجابة
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.
البطاقة ٤٢٧
السؤال
What does a positive control demonstrate?
الإجابة
That the setup can produce a known response. If it fails, the test system may be defective.
البطاقة ٤٢٨
السؤال
Why randomly assign subjects to experimental groups?
الإجابة
To distribute known and unknown differences more evenly. This reduces selection bias and confounding.
البطاقة ٤٢٩
السؤال
How can blinding reduce bias?
الإجابة
It keeps participants, observers, or both unaware of treatment assignments. Expectations are less likely to affect behavior or measurement.
البطاقة ٤٣٠
السؤال
What is a placebo?
الإجابة
An inactive treatment designed to resemble the experimental treatment. It helps separate treatment effects from expectation effects.
البطاقة ٤٣١
السؤال
What does a negative control demonstrate?
الإجابة
What happens when the tested cause is absent. An unexpected response may reveal contamination or another source.
البطاقة ٤٣٢
السؤال
Why does a larger sample often improve a study?
الإجابة
It reduces the influence of chance variation and supports more stable estimates. It cannot repair a biased sampling method.
البطاقة ٤٣٣
السؤال
Why repeat trials within an experiment?
الإجابة
To estimate variability and check consistency. One unusual trial then has less influence.
البطاقة ٤٣٤
السؤال
Why must an experimental procedure be detailed and standardized?
الإجابة
So groups are treated consistently and others can reproduce the work. Uncontrolled procedural differences create alternative explanations.
البطاقة ٤٣٥
السؤال
Why calibrate a measuring instrument before collecting data?
الإجابة
To compare its readings with a known standard and reduce systematic error. Calibration improves confidence in accuracy.
البطاقة ٤٣٦
السؤال
What is an operational definition?
الإجابة
A precise statement of how a variable is measured or manipulated. It turns an abstract concept into a repeatable procedure.
البطاقة ٤٣٧
السؤال
How does independent replication differ from repeated trials?
الإجابة
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.
البطاقة ٤٣٨
السؤال
Why should raw data be recorded before interpretation?
الإجابة
It preserves the observations separately from conclusions. Others can check calculations and reasoning.
البطاقة ٤٣٩
السؤال
What should a scientific conclusion do?
الإجابة
Answer the research question using the data and acknowledge limits. It should not claim more than the design supports.
البطاقة ٤٤٠
السؤال
What should happen when data do not support a hypothesis?
الإجابة
Revise or reject the hypothesis and consider new tests. Data should not be altered to preserve the original idea.
البطاقة ٤٤١
السؤال
What is a study limitation?
الإجابة
A feature that restricts interpretation or generalization. Small samples, short duration, and imperfect measurements are examples.
البطاقة ٤٤٢
السؤال
Why are ethics part of experimental design?
الإجابة
Research must protect participants, organisms, and communities while balancing risks and benefits. Consent and humane treatment are key examples.
البطاقة ٤٤٣
السؤال
How does an observational study differ from an experiment?
الإجابة
It measures variables without assigning the exposure. It can find associations but usually supports weaker causal conclusions.
البطاقة ٤٤٤
السؤال
Plants receive 0, 2, or 4 hours of added light, and growth is measured. What is the independent variable?
الإجابة
Hours of added light. Plant growth is the dependent variable.
البطاقة ٤٤٥
السؤال
A fertilizer study gives every plant the same water, soil, and temperature. What are these conditions?
الإجابة
Controlled variables. Keeping them constant isolates the fertilizer's effect.
البطاقة ٤٤٦
السؤال
A drug group improves more than a control group, but the groups were not randomly assigned. What is the main caution?
الإجابة
Preexisting group differences could explain some improvement. The result is suggestive, but the design weakens a causal claim.

Illustrated anatomy torso surrounded by a cell, DNA helix, molecule, flask, and data plot on a dark blue background.

٤٤٦ بطاقة