WGU Biochemistry OA – 100 MCQs (With Answers & Rationales

WGU Biochemistry OA – 100 MCQs (With
Answers & Rationales)
1–10: Biomolecules
1. Which bond links amino acids?
A. Glycosidic
B. Peptide ✅
C. Ester
D. Hydrogen
Rationale: Peptide bonds join amino acids.
2. Primary structure of protein refers to:
A. Folding
B. Sequence of amino acids ✅
C. Shape
D. Function
Rationale: Primary = amino acid sequence.
3. Which is a reducing sugar?
A. Sucrose
B. Lactose ✅
C. Starch
D. Glycogen
Rationale: Lactose has free aldehyde group.
4. Lipids are:
A. Hydrophilic
B. Amphipathic
C. Hydrophobic ✅
D. Charged
Rationale: Lipids repel water.
5. Phospholipids form:
A. Micelles
B. Bilayers ✅
C. Chains
D. Rings
Rationale: Cell membranes = bilayers.
6. DNA contains:
A. Ribose
B. Deoxyribose ✅
C. Glucose
D. Fructose
Rationale: DNA sugar is deoxyribose.

, 7. Which is NOT a protein function?
A. Catalysis
B. Structure
C. Energy storage ✅
D. Transport
Rationale: Proteins not primary energy storage.
8. Cholesterol is:
A. Protein
B. Carbohydrate
C. Steroid lipid ✅
D. Enzyme
Rationale: Cholesterol = steroid lipid.
9. Glycogen is stored in:
A. Brain
B. Liver & muscle ✅
C. Kidney
D. Blood
Rationale: Glycogen storage sites.
10. Hemoglobin carries:
A. CO₂
B. Oxygen ✅
C. Nitrogen
D. Hydrogen
Rationale: Oxygen transport protein.




11–25: Enzymes
11. Enzymes lower:
A. Energy
B. Activation energy ✅
C. Temperature
D. pH
Rationale: Speed reactions.
12. Active site binds:
A. Cofactor
B. Substrate ✅
C. Product
D. Enzyme
Rationale: Substrate fits active site.
13. Competitive inhibitors:
A. Bind elsewhere
B. Bind active site ✅
C. Destroy enzyme