Cell Structure & Function
A scientist places a cell in a solution containing a substance the cell needs. The substance is small enough to pass through the cell's outer boundary. However, the scientist notices that the cell is allowing some substances to enter while preventing others from leaving.
Which explanation best describes what is happening?
A. The cytoplasm is selecting which substances enter based on their usefulness.
B. The cell membrane regulates what enters and leaves the cell.
C. The nucleus is physically opening and closing pathways in the cell wall.
D. The mitochondria are filtering substances before they enter the cytoplasm.
WHAT IS
B. The cell membrane regulates what enters and leaves the cell.
A patient has a condition that prevents the small intestine from absorbing nutrients effectively. The patient continues eating regular meals but becomes weak over time.
Which explanation best connects the problem to the rest of the body?
A. Food is no longer entering the stomach, so the lungs cannot exchange oxygen.
B. Nutrients are not entering the bloodstream efficiently, reducing the materials available to cells.
C. The kidneys are unable to produce digestive enzymes, preventing the heart from beating.
D. The skeletal system is no longer transporting nutrients from the stomach.
WHAT IS
B. Nutrients are not entering the bloodstream efficiently, reducing the materials available to cells.
A student enters a dark room after spending several minutes outside in bright sunlight. At first, the student can barely see anything. After a few minutes, objects become easier to see.
Which explanation best describes what is occurring?
A. Mechanoreceptors in the eyes are detecting changes in air pressure.
B. Photoreceptors are adjusting their response to the lower light conditions.
C. Chemoreceptors are detecting chemicals released by the darkness.
D. Thermoreceptors are measuring the temperature difference between the rooms.
B. Photoreceptors are adjusting their response to the lower light conditions.
A student eats a meal containing carbohydrates. After digestion, glucose enters the bloodstream and is transported to muscle cells.
Which statement correctly describes the relationship between these systems?
A. The digestive system breaks down food, and the circulatory system transports absorbed nutrients.
B. The circulatory system digests food, and the muscular system transports glucose through the lungs.
C. The respiratory system absorbs glucose, and the skeletal system carries it to the muscles.
D. The nervous system produces glucose, and the excretory system transports it to the stomach.
WHAT IS
A. The digestive system breaks down food, and the circulatory system transports absorbed nutrients.
A scientist observes a cell that uses sunlight to produce glucose. The glucose is then used in cellular processes that help release usable energy.
Which statement correctly identifies the two organelles involved?
A. Chloroplasts capture light energy, and mitochondria help release usable energy from food.
B. Mitochondria capture sunlight, and ribosomes release energy from glucose.
C. Ribosomes capture light energy, and the nucleus converts glucose into oxygen.
D. The cell membrane produces glucose, and the vacuole releases energy.
WHAT IS
A. Chloroplasts capture light energy, and mitochondria help release usable energy from food.
Two cells are examined.
Cell A has many mitochondria and uses large amounts of energy.
Cell B has fewer mitochondria and requires less energy.
A scientist concludes that Cell A is probably more active in processes requiring energy.
Which evidence best supports this conclusion?
A. Mitochondria release usable energy from food, supporting cellular activities.
B. Mitochondria store genetic instructions that determine how active a cell becomes.
C. Mitochondria control the movement of all materials across the cell membrane.
D. Mitochondria produce the proteins that determine the cell's shape.
WHAT IS
A. Mitochondria release usable energy from food, supporting cellular activities.
A patient has healthy lungs that transfer oxygen into the blood. However, a damaged heart cannot pump blood efficiently.
Which result is most likely?
A. Oxygen enters the bloodstream but is not transported efficiently to body tissues.
B. Oxygen cannot enter the bloodstream because the heart controls gas exchange.
C. The digestive system begins producing oxygen to replace the missing circulation.
D. The kidneys immediately take over the heart's job of pumping blood.
WHAT TIME
A. Oxygen enters the bloodstream but is not transported efficiently to body tissues.
A student places a hand into a bowl of ice water. At first, the student notices the cold temperature. After several minutes, the cold sensation seems less intense.
Which statement is the best explanation?
A. The sensory system can adapt, causing the perceived intensity of a constant stimulus to decrease.
B. The photoreceptors in the skin stop detecting the temperature.
C. The nervous system stops communicating with the entire hand.
D. The skin changes cold temperatures into pressure signals.
WHAT IS
A. The sensory system can adapt, causing the perceived intensity of a constant stimulus to decrease.
A student touches a hot surface and pulls away. The student later explains that the hand moved before they consciously realized how hot the surface was.
Which statement best explains this?
A. The digestive system detects heat and sends instructions to the muscles.
B. Sensory information can trigger a reflex pathway through the nervous system that produces movement before conscious awareness.
C. The skeletal system independently detects temperature and moves the arm.
D. The muscular system processes information before the sensory receptors detect it.
WHAT IS
B. Sensory information can trigger a reflex pathway through the nervous system that produces movement before conscious awareness.
A person smells smoke, recognizes the smell as a possible danger, and moves toward an exit. During this event, the person also begins breathing faster.
Which sequence best represents the relationship between sensory information and the body's response?
A. Chemoreceptors detect chemicals, the nervous system processes information, and body systems coordinate a response.
B. Mechanoreceptors detect chemicals, the digestive system makes a decision, and the skeletal system increases breathing.
C. Photoreceptors detect smoke, the muscular system processes information, and the circulatory system identifies danger.
D. Thermoreceptors detect smoke, the respiratory system processes information, and the digestive system controls movement.
WHAT IS
A. Chemoreceptors detect chemicals, the nervous system processes information, and body systems coordinate a response.
A cell's ribosomes stop functioning properly. At first, the cell is still able to obtain nutrients and release energy. However, over time, the cell cannot maintain many of its normal activities.
What is the most direct reason for this problem?
A. The cell can no longer control which materials cross its membrane.
B. The cell can no longer assemble the proteins needed to build and maintain its structures.
C. The cell can no longer store water and other materials in its vacuoles.
D. The cell can no longer use its nucleus to produce energy.
WHAT IS
B. The cell can no longer assemble the proteins needed to build and maintain its structures.
A person has a spinal cord injury that interrupts communication between the brain and certain muscles below the injury.
The person's muscles may still contain healthy muscle cells, but voluntary movement is affected.
Which explanation is best?
A. The skeletal system normally sends electrical instructions directly to the brain.
B. The nervous system provides communication pathways needed to coordinate muscle movement.
C. The circulatory system normally controls all voluntary movement by carrying oxygen.
D. The muscular system normally creates sensory information without help from the nervous system.
WHAT IS
B. The nervous system provides communication pathways needed to coordinate muscle movement.
A student is wearing headphones when a loud bass sound begins playing. The student can feel the vibrations against the skin and hear the sound.
Which statement correctly identifies the receptors involved?
A. Photoreceptors detect both the sound and skin vibrations.
B. Chemoreceptors detect the sound, while thermoreceptors detect the vibrations.
C. Mechanoreceptors respond to sound vibrations in the ear and physical vibrations against the skin.
D. Thermoreceptors detect the sound because it creates energy.
WHAT IS
C. Mechanoreceptors respond to sound vibrations in the ear and physical vibrations against the skin.
A student has a healthy digestive system but a circulatory condition that prevents nutrients from being transported effectively.
Why could this still cause problems for cells throughout the body?
A. Digestion alone does not guarantee that nutrients reach cells; the circulatory system transports them.
B. The digestive system normally pumps nutrients directly into every cell without blood.
C. The circulatory system is responsible for breaking food into smaller molecules.
D. Cells manufacture all their nutrients, so circulation does not affect them.
WHAT IS
A. Digestion alone does not guarantee that nutrients reach cells; the circulatory system transports them.
A scientist compares two groups of cells.
Group A has functioning nuclei but damaged ribosomes.
Group B has functioning ribosomes but damaged nuclei.
Which statement best predicts the difference between these groups?
A. Group A will have difficulty making proteins, while Group B will have difficulty controlling cell activities through its genetic instructions.
B. Group A will be unable to control what enters the cell, while Group B will be unable to release energy from food.
C. Group A will lose its cell membrane, while Group B will lose its mitochondria.
D. Both groups will function normally because neither nucleus nor ribosomes are essential.
WHAT IS
A. Group A will have difficulty making proteins, while Group B will have difficulty controlling cell activities through its genetic instructions.
A scientist discovers a cell with a nucleus, mitochondria, a cell membrane, and a large central vacuole. The cell also has a rigid outer structure.
Which additional observation would provide the strongest evidence that this cell is a plant cell rather than an animal cell?
A. It contains cytoplasm surrounding its organelles.
B. It contains genetic information inside its nucleus.
C. It contains chloroplasts that capture light energy.
D. It contains mitochondria that release usable energy.
WHAT IS
C. It contains chloroplasts that capture light energy.
A person exercises for an extended period without drinking water. The body begins conserving water, and the kidneys adjust how much water is removed in urine.
Which two systems are most directly involved in this situation?
A. Digestive and skeletal
B. Respiratory and muscular
C. Excretory and circulatory
D. Nervous and integumentary
WHAT IS
C. Excretory and circulatory
A person can see a red traffic light but cannot distinguish the color red from other colors. The person can still detect that the light is bright.
Which explanation is most reasonable?
A. All photoreceptors have stopped working, so the person should be unable to detect light.
B. Some specialized photoreceptor functions may be impaired while other light-detection abilities remain.
C. The person's mechanoreceptors are interpreting red light as pressure.
D. The person's chemoreceptors are preventing the eyes from detecting color.
WHAT IS
B. Some specialized photoreceptor functions may be impaired while other light-detection abilities remain.
During exercise, muscle cells increase their energy demands. The respiratory system increases oxygen intake, and the circulatory system increases blood delivery.
What is the most accurate explanation for this coordinated response?
A. The systems work together to provide cells with oxygen and nutrients needed to release usable energy from food.
B. The respiratory system produces energy directly, while the circulatory system removes all glucose.
C. The muscular system takes control of the lungs and heart and makes them unnecessary.
D. The skeletal system converts oxygen into nutrients before blood transports them.
WHAT IS
A. The systems work together to provide cells with oxygen and nutrients needed to release usable energy from food.
A student has damage to sensory receptors that detect changes in temperature. The student touches a hot object but does not recognize the temperature change normally.
Which statement best describes the problem?
A. The stimulus does not exist because the student cannot detect it.
B. The sensory receptors are not effectively detecting the stimulus, which can interfere with the nervous system's ability to coordinate an appropriate response.
C. The student's muscles have stopped functioning because the receptors control muscle structure.
D. The student's circulatory system is preventing the object from transferring heat.
WHAT IS
B. The sensory receptors are not effectively detecting the stimulus, which can interfere with the nervous system's ability to coordinate an appropriate response.
A chemical damages the mitochondria in a group of muscle cells. The cells still have functioning nuclei, ribosomes, and cell membranes.
After several hours, the muscle tissue begins having difficulty performing its normal activities.
Which prediction is most scientifically reasonable?
A. The cells will immediately lose their genetic information because mitochondria control the nucleus.
B. The cells will have difficulty obtaining enough usable energy to support normal activities, even though other organelles still function.
C. The cells will begin producing unlimited energy because damaged mitochondria cause ribosomes to work faster.
D. The cells will stop allowing all substances to enter because mitochondria form the cell membrane.
WHAT IS
B. The cells will have difficulty obtaining enough usable energy to support normal activities, even though other organelles still function.
A patient has a disorder that damages the tiny air sacs in the lungs. These structures normally allow oxygen and carbon dioxide to move between the air and the blood.
The patient begins experiencing fatigue, even though the heart and muscles are structurally healthy.
Which chain of events best explains the fatigue?
A. Damaged air sacs reduce oxygen entering the blood, decreasing oxygen delivery to cells and interfering with cellular energy release.
B. Damaged air sacs prevent nutrients from entering the digestive tract, stopping the kidneys from filtering blood.
C. Damaged air sacs stop the nervous system from detecting stimuli, preventing muscles from receiving nutrients.
D. Damaged air sacs prevent the skeletal system from producing red blood cells, immediately stopping all movement.
WHAT IS
A. Damaged air sacs reduce oxygen entering the blood, decreasing oxygen delivery to cells and interfering with cellular energy release.
During an experiment, a student is exposed to four stimuli:
A bright flash of light.
A sudden increase in air temperature.
A strong odor.
A vibrating tuning fork touching the skin.
The student has damage affecting only the mechanoreceptors.
Which response would most likely be impaired?
A. Detecting the bright flash and the increase in temperature.
B. Detecting the strong odor and the bright flash.
C. Detecting the odor and the temperature increase.
D. Detecting the physical vibration while still detecting the other three stimuli.
WHAT IS
D. Detecting the physical vibration while still detecting the other three stimuli.
A person experiences damage to the nervous system that interferes with communication between the brain and the sweat glands. During exercise, the person does not sweat normally.
Why could this become dangerous?
A. The sweat glands normally pump blood, so the heart will stop circulating oxygen.
B. The nervous system helps regulate sweating, and reduced sweating can interfere with the body's ability to release heat.
C. The digestive system will stop breaking down food because sweating is required for digestion.
D. The skeletal system will lose its ability to produce white blood cells.
WHAT IS
B. The nervous system helps regulate sweating, and reduced sweating can interfere with the body's ability to release heat
A scientist studies a patient with the following observations:
The patient's sensory receptors detect a change in the environment.
The nervous system receives and processes the information.
The patient's heart and lungs respond normally.
However, certain muscle cells cannot produce enough usable energy because their mitochondria are damaged.
Which conclusion best explains why the patient may still struggle to respond physically to the stimulus?
A. Detecting a stimulus automatically guarantees movement, regardless of whether muscle cells have enough energy.
B. The nervous system may correctly coordinate a response, but muscle cells still need usable energy to carry out the movement.
C. Mitochondria are responsible for detecting the stimulus, so the nervous system cannot receive information.
D. The cell membrane replaces mitochondria when muscle cells need energy, so movement should remain completely normal.
WHAT IS
B. The nervous system may correctly coordinate a response, but muscle cells still need usable energy to carry out the movement.