WGU C190 INTRODUCTION TO
BIOLOGY COMPREHENSIVE EXAM
2026 QUESTIONS AND ANSWERS
1. Which of the following best describes the role of an enzyme in a biochemical reaction?
A. Enzymes increase the activation energy required for a reaction to proceed.
B. Enzymes are consumed during the reaction and must be replenished.
C. Enzymes lower the activation energy, thereby increasing the rate of the reaction.
D. Enzymes change the equilibrium constant of a chemical reaction.
Answer: C
Conceptual Explanation: Enzymes act as biological catalysts by lowering the activation
energy barrier, allowing reactions to occur faster without being consumed or changing the
reaction’s equilibrium.
2. In the fluid mosaic model of the plasma membrane, what is the primary function of
cholesterol?
A. It acts as a channel for ions to pass through the membrane.
B. It regulates membrane fluidity across a range of temperatures.
,C. It serves as the primary site for ATP synthesis.
D. It facilitates the active transport of glucose molecules.
Answer: B
Conceptual Explanation: Cholesterol acts as a fluidity buffer, preventing the membrane
from becoming too rigid in cold temperatures and too fluid in high temperatures.
3. If a red blood cell is placed in a hypertonic solution, what will most likely occur?
A. The cell will swell and potentially burst (lyse).
B. Water will move into the cell by osmosis.
C. There will be no net movement of water.
D. The cell will shrink due to water loss.
Answer: D
Conceptual Explanation: In a hypertonic solution, the solute concentration outside the
cell is higher than inside, causing water to move out of the cell, leading to crenation
(shrinking).
4. During which phase of mitosis do sister chromatids separate and move toward opposite
poles?
A. Prophase
B. Anaphase
C. Metaphase
, D. Telophase
Answer: B
Conceptual Explanation: Anaphase is characterized by the shortening of spindle fibers
and the separation of sister chromatids into individual chromosomes moving to opposite
ends of the cell.
5. What is the primary significance of crossing over during Prophase I of meiosis?
A. It ensures that the daughter cells are genetically identical to the parent cell.
B. It reduces the chromosome number from diploid to haploid.
C. It increases genetic variation by exchanging DNA between homologous chromosomes.
D. It prevents mutations from occurring during DNA replication.
Answer: C
Conceptual Explanation: Crossing over involves the exchange of genetic material between
non-sister chromatids of homologous chromosomes, resulting in new combinations of
alleles.
6. In cellular respiration, what is the net yield of ATP produced solely through glycolysis per
molecule of glucose?
A. 32 ATP
B. 4 ATP
C. 2 ATP
BIOLOGY COMPREHENSIVE EXAM
2026 QUESTIONS AND ANSWERS
1. Which of the following best describes the role of an enzyme in a biochemical reaction?
A. Enzymes increase the activation energy required for a reaction to proceed.
B. Enzymes are consumed during the reaction and must be replenished.
C. Enzymes lower the activation energy, thereby increasing the rate of the reaction.
D. Enzymes change the equilibrium constant of a chemical reaction.
Answer: C
Conceptual Explanation: Enzymes act as biological catalysts by lowering the activation
energy barrier, allowing reactions to occur faster without being consumed or changing the
reaction’s equilibrium.
2. In the fluid mosaic model of the plasma membrane, what is the primary function of
cholesterol?
A. It acts as a channel for ions to pass through the membrane.
B. It regulates membrane fluidity across a range of temperatures.
,C. It serves as the primary site for ATP synthesis.
D. It facilitates the active transport of glucose molecules.
Answer: B
Conceptual Explanation: Cholesterol acts as a fluidity buffer, preventing the membrane
from becoming too rigid in cold temperatures and too fluid in high temperatures.
3. If a red blood cell is placed in a hypertonic solution, what will most likely occur?
A. The cell will swell and potentially burst (lyse).
B. Water will move into the cell by osmosis.
C. There will be no net movement of water.
D. The cell will shrink due to water loss.
Answer: D
Conceptual Explanation: In a hypertonic solution, the solute concentration outside the
cell is higher than inside, causing water to move out of the cell, leading to crenation
(shrinking).
4. During which phase of mitosis do sister chromatids separate and move toward opposite
poles?
A. Prophase
B. Anaphase
C. Metaphase
, D. Telophase
Answer: B
Conceptual Explanation: Anaphase is characterized by the shortening of spindle fibers
and the separation of sister chromatids into individual chromosomes moving to opposite
ends of the cell.
5. What is the primary significance of crossing over during Prophase I of meiosis?
A. It ensures that the daughter cells are genetically identical to the parent cell.
B. It reduces the chromosome number from diploid to haploid.
C. It increases genetic variation by exchanging DNA between homologous chromosomes.
D. It prevents mutations from occurring during DNA replication.
Answer: C
Conceptual Explanation: Crossing over involves the exchange of genetic material between
non-sister chromatids of homologous chromosomes, resulting in new combinations of
alleles.
6. In cellular respiration, what is the net yield of ATP produced solely through glycolysis per
molecule of glucose?
A. 32 ATP
B. 4 ATP
C. 2 ATP
