SLCC 2420 Physiology – Green – Spring Final Exam | Complete
Questions with Correct Answers and Informative Rationales –
2026
Question 1. Which statement best describes homeostasis?
A. Maintenance of a completely unchanging internal environment
B. Maintenance of a relatively stable internal environment despite external
changes
C. Elimination of all physiological changes
D. Regulation of only body temperature
Correct Answer: B
Rationale: Homeostasis is the body's ability to maintain relatively stable
internal conditions within a physiological range. It does not mean that
variables remain absolutely constant; instead, systems continuously adjust
conditions such as temperature, blood glucose, pH, and blood pressure.
Question 2. Which mechanism is most commonly responsible for maintaining
homeostasis?
A. Positive feedback
B. Negative feedback
C. Feedforward inhibition only
D. Random physiological activity
Correct Answer: B
Rationale: Negative feedback reverses or reduces a change from a normal
range. For example, when body temperature rises, mechanisms such as
sweating and increased skin blood flow help lower temperature toward its
normal range.
Question 3. Which is an example of positive feedback?
1
,A. Regulation of body temperature
B. Regulation of blood glucose
C. Blood clotting
D. Regulation of blood pressure
Correct Answer: C
Rationale: Positive feedback amplifies an initial change rather than opposing
it. During blood clotting, activated platelets promote activation of additional
platelets, rapidly strengthening the clot until the process is completed.
Question 4. Which organelle is primarily responsible for producing ATP in
aerobic cells?
A. Ribosome
B. Lysosome
C. Mitochondrion
D. Golgi apparatus
Correct Answer: C
Rationale: Mitochondria generate most cellular ATP through aerobic
metabolism, particularly during the citric acid cycle and oxidative
phosphorylation. ATP provides energy for processes such as active transport,
muscle contraction, and biosynthesis.
Question 5. Which transport mechanism requires cellular energy in the form
of ATP?
A. Simple diffusion
B. Facilitated diffusion
C. Osmosis
D. Primary active transport
Correct Answer: D
2
,Rationale: Primary active transport directly uses ATP to move substances
against their concentration or electrochemical gradients. The sodium-
potassium pump is a major example, moving sodium out of cells and
potassium into cells.
Question 6. What happens to a cell placed in a hypotonic solution?
A. It loses water and shrinks
B. It gains water and may swell
C. There is no movement of water
D. It immediately loses all intracellular ions
Correct Answer: B
Rationale: A hypotonic extracellular solution has a lower effective solute
concentration than the cell. Water moves into the cell through osmosis,
causing the cell to swell and potentially rupture if the difference is sufficiently
large.
Question 7. Which substance can cross a cell membrane most easily by
simple diffusion?
A. Sodium ion
B. Glucose
C. Oxygen
D. Large protein
Correct Answer: C
Rationale: Oxygen is small and nonpolar, allowing it to dissolve in the lipid
portion of the cell membrane and diffuse directly through it. Charged ions and
large polar molecules generally require membrane transport proteins.
Question 8. What is the resting membrane potential of a typical neuron
primarily related to?
3
, A. Equal distribution of ions on both sides of the membrane
B. Ion concentration gradients and selective membrane permeability
C. Absence of potassium inside the cell
D. Continuous opening of every ion channel
Correct Answer: B
Rationale: Resting membrane potential results from unequal ion
concentrations across the membrane, selective permeability—especially to
potassium—and maintenance of these gradients by ion pumps such as the
sodium-potassium ATPase.
Question 9. Which ion is present at a higher concentration inside most cells
than outside?
A. Sodium
B. Calcium
C. Potassium
D. Chloride
Correct Answer: C
Rationale: Potassium concentration is normally much higher inside cells,
while sodium concentration is higher extracellularly. These gradients are
essential for nerve impulses, muscle contraction, and membrane potentials.
Question 10. What is the primary function of the sodium-potassium pump?
A. Move sodium and potassium down their concentration gradients
B. Move sodium into the cell and potassium out of the cell
C. Move sodium out of the cell and potassium into the cell using ATP
D. Transport calcium into the nucleus
Correct Answer: C
4
Questions with Correct Answers and Informative Rationales –
2026
Question 1. Which statement best describes homeostasis?
A. Maintenance of a completely unchanging internal environment
B. Maintenance of a relatively stable internal environment despite external
changes
C. Elimination of all physiological changes
D. Regulation of only body temperature
Correct Answer: B
Rationale: Homeostasis is the body's ability to maintain relatively stable
internal conditions within a physiological range. It does not mean that
variables remain absolutely constant; instead, systems continuously adjust
conditions such as temperature, blood glucose, pH, and blood pressure.
Question 2. Which mechanism is most commonly responsible for maintaining
homeostasis?
A. Positive feedback
B. Negative feedback
C. Feedforward inhibition only
D. Random physiological activity
Correct Answer: B
Rationale: Negative feedback reverses or reduces a change from a normal
range. For example, when body temperature rises, mechanisms such as
sweating and increased skin blood flow help lower temperature toward its
normal range.
Question 3. Which is an example of positive feedback?
1
,A. Regulation of body temperature
B. Regulation of blood glucose
C. Blood clotting
D. Regulation of blood pressure
Correct Answer: C
Rationale: Positive feedback amplifies an initial change rather than opposing
it. During blood clotting, activated platelets promote activation of additional
platelets, rapidly strengthening the clot until the process is completed.
Question 4. Which organelle is primarily responsible for producing ATP in
aerobic cells?
A. Ribosome
B. Lysosome
C. Mitochondrion
D. Golgi apparatus
Correct Answer: C
Rationale: Mitochondria generate most cellular ATP through aerobic
metabolism, particularly during the citric acid cycle and oxidative
phosphorylation. ATP provides energy for processes such as active transport,
muscle contraction, and biosynthesis.
Question 5. Which transport mechanism requires cellular energy in the form
of ATP?
A. Simple diffusion
B. Facilitated diffusion
C. Osmosis
D. Primary active transport
Correct Answer: D
2
,Rationale: Primary active transport directly uses ATP to move substances
against their concentration or electrochemical gradients. The sodium-
potassium pump is a major example, moving sodium out of cells and
potassium into cells.
Question 6. What happens to a cell placed in a hypotonic solution?
A. It loses water and shrinks
B. It gains water and may swell
C. There is no movement of water
D. It immediately loses all intracellular ions
Correct Answer: B
Rationale: A hypotonic extracellular solution has a lower effective solute
concentration than the cell. Water moves into the cell through osmosis,
causing the cell to swell and potentially rupture if the difference is sufficiently
large.
Question 7. Which substance can cross a cell membrane most easily by
simple diffusion?
A. Sodium ion
B. Glucose
C. Oxygen
D. Large protein
Correct Answer: C
Rationale: Oxygen is small and nonpolar, allowing it to dissolve in the lipid
portion of the cell membrane and diffuse directly through it. Charged ions and
large polar molecules generally require membrane transport proteins.
Question 8. What is the resting membrane potential of a typical neuron
primarily related to?
3
, A. Equal distribution of ions on both sides of the membrane
B. Ion concentration gradients and selective membrane permeability
C. Absence of potassium inside the cell
D. Continuous opening of every ion channel
Correct Answer: B
Rationale: Resting membrane potential results from unequal ion
concentrations across the membrane, selective permeability—especially to
potassium—and maintenance of these gradients by ion pumps such as the
sodium-potassium ATPase.
Question 9. Which ion is present at a higher concentration inside most cells
than outside?
A. Sodium
B. Calcium
C. Potassium
D. Chloride
Correct Answer: C
Rationale: Potassium concentration is normally much higher inside cells,
while sodium concentration is higher extracellularly. These gradients are
essential for nerve impulses, muscle contraction, and membrane potentials.
Question 10. What is the primary function of the sodium-potassium pump?
A. Move sodium and potassium down their concentration gradients
B. Move sodium into the cell and potassium out of the cell
C. Move sodium out of the cell and potassium into the cell using ATP
D. Transport calcium into the nucleus
Correct Answer: C
4
