BIO 201 MIDTERM EXAM – ANATOMY
& PHYSIOLOGY I QUESTIONS WITH
CORRECT ANSWERS (LATEST 2026 /
2027), (A+ GUARANTEE).
1. A patient presents with a blood pH of 7.25. Which of the following best describes this
condition and the likely physiological response?
A. Alkalosis; the kidneys will decrease bicarbonate reabsorption.
B. Alkalosis; the kidneys will increase H+ secretion.
C. Acidosis; the respiratory rate will decrease to retain CO2.
D. Acidosis; the respiratory rate will increase to expel CO2.
Answer: D
Conceptual Explanation: Normal blood pH is 7.35-7.45. A pH of 7.25 indicates acidosis.
The body compensates by increasing respiration to lower CO2 levels, thereby raising pH.
2. In the fluid mosaic model of the plasma membrane, what is the primary function of
cholesterol?
A. To act as a primary energy source for active transport.
B. To stabilize the membrane and regulate its fluidity across temperatures.
C. To facilitate the movement of hydrophilic ions across the bilayer.
,D. To serve as a recognition site for hormone binding.
Answer: B
Conceptual Explanation: Cholesterol wedged between phospholipids prevents the
membrane from becoming too fluid at high temperatures or too rigid at low temperatures.
3. Which level of protein structure is characterized by the sequence of amino acids linked by
peptide bonds?
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
Answer: A
Conceptual Explanation: Primary structure refers solely to the linear sequence of amino
acids. Secondary involves alpha-helices and beta-sheets.
4. During which phase of the cell cycle does DNA polymerase catalyze the synthesis of new
DNA strands?
A. G1 phase
B. S phase
C. G2 phase
D. M phase
, Answer: B
Conceptual Explanation: DNA replication occurs exclusively during the S (Synthesis)
phase of interphase.
5. A red blood cell placed in a solution with a 5% NaCl concentration will undergo:
A. Hemolysis due to a hypotonic environment.
B. Active transport of water into the cell.
C. No change because it is an isotonic environment.
D. Crenation due to a hypertonic environment.
Answer: D
Conceptual Explanation: Physiological saline is 0.9%. A 5% solution is hypertonic,
causing water to leave the cell by osmosis, resulting in shriveling (crenation).
6. Which organelle is responsible for the detoxification of drugs and the synthesis of steroid-
based hormones?
A. Rough Endoplasmic Reticulum
B. Golgi Apparatus
C. Smooth Endoplasmic Reticulum
D. Lysosome
Answer: C
& PHYSIOLOGY I QUESTIONS WITH
CORRECT ANSWERS (LATEST 2026 /
2027), (A+ GUARANTEE).
1. A patient presents with a blood pH of 7.25. Which of the following best describes this
condition and the likely physiological response?
A. Alkalosis; the kidneys will decrease bicarbonate reabsorption.
B. Alkalosis; the kidneys will increase H+ secretion.
C. Acidosis; the respiratory rate will decrease to retain CO2.
D. Acidosis; the respiratory rate will increase to expel CO2.
Answer: D
Conceptual Explanation: Normal blood pH is 7.35-7.45. A pH of 7.25 indicates acidosis.
The body compensates by increasing respiration to lower CO2 levels, thereby raising pH.
2. In the fluid mosaic model of the plasma membrane, what is the primary function of
cholesterol?
A. To act as a primary energy source for active transport.
B. To stabilize the membrane and regulate its fluidity across temperatures.
C. To facilitate the movement of hydrophilic ions across the bilayer.
,D. To serve as a recognition site for hormone binding.
Answer: B
Conceptual Explanation: Cholesterol wedged between phospholipids prevents the
membrane from becoming too fluid at high temperatures or too rigid at low temperatures.
3. Which level of protein structure is characterized by the sequence of amino acids linked by
peptide bonds?
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
Answer: A
Conceptual Explanation: Primary structure refers solely to the linear sequence of amino
acids. Secondary involves alpha-helices and beta-sheets.
4. During which phase of the cell cycle does DNA polymerase catalyze the synthesis of new
DNA strands?
A. G1 phase
B. S phase
C. G2 phase
D. M phase
, Answer: B
Conceptual Explanation: DNA replication occurs exclusively during the S (Synthesis)
phase of interphase.
5. A red blood cell placed in a solution with a 5% NaCl concentration will undergo:
A. Hemolysis due to a hypotonic environment.
B. Active transport of water into the cell.
C. No change because it is an isotonic environment.
D. Crenation due to a hypertonic environment.
Answer: D
Conceptual Explanation: Physiological saline is 0.9%. A 5% solution is hypertonic,
causing water to leave the cell by osmosis, resulting in shriveling (crenation).
6. Which organelle is responsible for the detoxification of drugs and the synthesis of steroid-
based hormones?
A. Rough Endoplasmic Reticulum
B. Golgi Apparatus
C. Smooth Endoplasmic Reticulum
D. Lysosome
Answer: C
