Biochemistry- Module 4 QUESTIONS AND
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CHEM 210 Biochemistry — Module 4 Practice Exam
Carbohydrates: Structure, Function, and Reactivity
50 Challenging Practice Questions with Answers + Explanations
Monosaccharides & Stereochemistry
1. Which monosaccharide shown below is a ketose (carbonyl on C2) rather than an aldose?
A. D-Glucose
B. D-Ribose
C. Dihydroxyacetone
D. D-Galactose
Answer: C
Explanation: Dihydroxyacetone is the simplest ketose; its carbonyl is at C2. (docsity.com)
2. What defines two sugars as epimers?
A. They differ only in ring size
B. They differ in configuration at one chiral carbon
C. They differ in carbon chain length
D. One is a sugar alcohol
Answer: B
Explanation: Epimers differ only by configuration at one stereocenter. (docsity.com)
,3. Which carbon determines whether a sugar is D or L configuration?
A. Anomeric carbon
B. Carbonyl carbon
C. Penultimate carbon
D. Carbon bonded to the phosphate
Answer: C
Explanation: The penultimate (next-to-last) carbon’s orientation defines D or L. (docsity.com)
4. In the Fischer projection of D-glucose, the hydroxyl group on C2 is on the:
A. Left
B. Right
C. Top
D. Bottom
Answer: B
Explanation: For D-glucose, the OH on C2 is on the right in Fischer form.
5. Which pair of sugars are anomers of each other?
A. α-D-Glucose and β-D-Glucose
B. D-Glucose and D-Fructose
C. D-Galactose and D-Glucose
D. α-D-Glucose and α-L-Glucose
Answer: A
Explanation: Anomers differ at the anomeric carbon (α vs β). (docsity.com)
Ring Structures & Mutarotation
6. The ring form of a hexose with a five-membered ring is called a:
A. Pyranose
B. Furanose
C. Cyclic ester
D. Epimer
Answer: B
Explanation: A five-membered sugar ring is a furanose. (docsity.com)
, 7. Mutarotation refers to:
A. Conversion of aldoses to ketoses
B. Change in optical rotation as α and β anomers interconvert in solution
C. Hydrolysis of glycosidic bonds
D. Reduction to sugar alcohols
Answer: B
Explanation: Mutarotation is the interconversion between α/β anomers in solution.
8. The anomeric carbon in α-D-glucopyranose is:
A. C1
B. C2
C. C3
D. C6
Answer: A
Explanation: In glucose, the anomeric carbon is C1. (docsity.com)
Disaccharides & Glycosidic Bonds
9. In maltose, the glycosidic linkage between the two glucose units is:
A. α(1→4)
B. β(1→4)
C. α(1→6)
D. β(1→2)
Answer: A
Explanation: Maltose has an α(1→4) linkage. (docsity.com)
10. Lactose is a disaccharide composed of:
A. Glucose + Fructose
B. Glucose + Galactose
C. Galactose + Fructose
D. Glucose + Glucose
Answer: B
Explanation: Lactose = Galactose + Glucose with β(1→4) glycosidic bond.