BIOD 171 Module 2 Exam 2026 | Portage Learning | Microscopy & Cell Structure | Verified Q&As + Practice Set

BIOD 171 Module 2: Exam Portage Learning Questions and Answers 2026 Practice
Set


1. Which of the following best defines "metabolism"?
A) The breakdown of food into waste
B) The production of ATP only
C) The sum of all chemical reactions in a cell
D) The movement of a cell via flagella
Rationale: Metabolism is the total of all biochemical processes, including those that
break down molecules for energy and those that build complex structures.
2. An "anabolic" pathway is one that:
A) Consumes energy to build complex molecules from simpler ones
B) Releases energy by breaking down complex molecules
C) Occurs only in the absence of oxygen
D) Functions without the use of enzymes
Rationale: Anabolism is the "building" phase of metabolism (e.g., protein synthesis),
which requires an input of energy (ATP).
3. What is the role of an enzyme in a chemical reaction?
A) To increase the temperature of the reaction
B) To lower the activation energy required for the reaction
C) To be consumed as a reactant
D) To change the final equilibrium of the products
Rationale: Enzymes are biological catalysts; they speed up reactions by lowering the
"energy barrier" (activation energy) needed to start the process.
4. The specific location on an enzyme where the substrate binds is called the:
A) Allosteric site
B) Active site
C) Coenzyme
D) Product site
Rationale: The active site has a specific shape and chemical environment that matches
the substrate, often described by the "lock and key" or "induced fit" models.
5. Which molecule is considered the "energy currency" of the cell?
A) Glucose
B) NADH
C) ATP

,D) DNA
Rationale: Adenosine Triphosphate (ATP) is the primary molecule used by cells to
transfer and spend energy for immediate work.
6. In a REDOX reaction, "reduction" refers to the:
A) Loss of an electron
B) Gain of an electron
C) Loss of a proton
D) Gain of a phosphate
Rationale: Remember OIL RIG: Oxidation Is Loss, Reduction Is Gain (of electrons).
7. Where does Glycolysis occur in both prokaryotic and eukaryotic cells?
A) Mitochondria
B) Cytoplasm
C) Nucleus
D) Plasma membrane
Rationale: Glycolysis is a universal pathway that takes place in the cytosol/cytoplasm
of the cell.
8. What is the "starting" molecule for Glycolysis?
A) Pyruvate
B) Glucose
C) Acetyl-CoA
D) Citrate
Rationale: Glycolysis literally means "sugar splitting," where one 6-
carbon glucose molecule is broken down.
9. What is the net gain of ATP produced during Glycolysis?
A) 2 ATP
B) 4 ATP
C) 34 ATP
D) 0 ATP
Rationale: While Glycolysis produces 4 ATP, it requires an investment of 2 ATP at the
start, resulting in a net gain of 2.
10. If oxygen is NOT present, pyruvate undergoes which process?
A) TCA Cycle
B) Electron Transport Chain
C) Fermentation
D) Beta-oxidation

, Rationale: Fermentation allows the cell to regenerate NAD+ so Glycolysis can continue
in anaerobic (oxygen-free) conditions.
11. Which of the following is a byproduct of fermentation in muscle cells?
A) Ethanol
B) Lactic acid
C) Oxygen
D) Acetyl-CoA
Rationale: Animal cells and some bacteria perform lactic acid fermentation, while
yeast typically produces ethanol and


.
12. Before entering the TCA (Krebs) Cycle, pyruvate must be converted into:
A) Glucose
B) Acetyl-CoA
C) Lactate
D) Oxaloacetate
Rationale: The intermediate step involves the decarboxylation of pyruvate to
form Acetyl-CoA, which then enters the cycle.
13. How many turns of the TCA Cycle are required to process one molecule of
glucose?
A) 1
B) 2
C) 4
D) 6
Rationale: One glucose molecule produces two pyruvate molecules; therefore, the
cycle must turn twice to process the original glucose.
14. What are the primary electron carriers produced during the TCA Cycle?
A) ATP and ADP
B) NADH and



C) Glucose and Oxygen
D)

and