Biochemistry MCQ-01: Carbohydrates, one of the most essential classes of biomolecules, are critical for providing energy, building cell structures, and storing information. Understanding the properties and functions of carbohydrates is therefore essential for any student of biochemistry. The present a set of MCQ on Carbohydrates is designed to challenge and expand your knowledge of this fundamental class of this biomolecule.
Learn more: Carbohydrates MCQ Part-2 | Part-3 |
1. The general chemical formula of carbohydrate is
a. (CH2O)n
b. (CH2O)2n
c. (CHO)n
d. CnH2nO
2. Which of the following is an aldotriose?
a. Dihydroxyacetone
b. Glyceraldehyde
c. Ribulose
d. Erythrose
3. What is the molecular formula of sucrose?
a. C12H22O11
b. C10H20O10
c. C6H12O6
d. C12H20O11
4. The glycosidic linkage between glucose molecule in maltose is
a. β 1 – 4
b. α 1 – 2
c. α 1 – 4
d. β 1 – 2
Note on Carbohydrates | Monosacchrides | Disaccharides | Polysaccharides | Sugar Derivates | Glycosaminoglycans | Glycoconjugates |
5. A keto pentose will have _____ sterioisomers.
a. 4
b. 6
c. 8
d. 10
6. The reserve food material of green algae is
a. Laminarin
b. Chrysolaminarin
c. Floridian starch
d. Starch
7. The only carbohydrate which is not having any chiral carbon atom is
a. Glyceraldehyde
b. Erythrose
c. Dihydroxyacetone
d. Erythrulose
8. Select the odd one from the following.
a. Arabinose
b. Xylose
c. Lyxose
d. Erythrose
9. A pentose sugar reported to be present in heart cells
a. Xylose
b. Arabinose
c. Lyxose
d. Xylulose
10. Which of the following is an epimeric pair?
a. D-glucose and D-mannose
b. D-glucose and D-galactose
c. D-glucose and L-glucose
d. Both A and B
11. Select the odd one from the following
a. Xylulose
b. Dihydroxyacetone
c. Glyceraldehyde
d. Ribulose
12. Which of the following sugar give a positive result with Seliwanoff test
a. Sucrose
b. Glucose
c. Galactose
d. Mannose
13. Which of the following is a keto tetrose?
a. Erythrulose
b. Xylulose
c. Sorbose
d. Psicose
14. The glycosidic linkage between two glucose molecules in isomaltose is
a. α 1 – 4
b. β 1 – 4
c. α 1 – 6
d. β 1 – 6
15. Which of the following is an alpha lactone
a. Vit. C
b. Vit. D
c. Vit. A
d. Vit. K
16. A sweetener used in sugar less gums and candies
a. Ribitol
b. Xylitol
c. Inositol
d. Mannitol
17. The glycosidic linkage in cellobiose is
a. α 1 – 4
b. β 1 – 4
c. α 1 – 6
d. β 1 – 6
18. Pick out the odd one from the following
a. Deoxyribose
b. Rhamnose
c. Fucose
d. Altrose
19. Lectins are_________.
a. Sugars specific to proteins
b. Proteins specific to sugars
c. Enzymes specific to carbohydrates
d. Carbohydrates specific to enzymes
20. Which of the following is a keto triose?
a. Dihydroxyacetone
b. Glyceraldehyde
c. Ribulose
d. Erythrose
21. Maltose is a disaccharide of ____
a. Glucose and galactose
b. Glucose and glucose
c. Glucose and lactose
d. Fructose and lactose
22. Glycosidic bond in sucrose is____
a. α 1 – 4
b. β 1 – 4
c. α 1 – 2
d. β 1 – 2
23. Minimum number of carbon required for a ketose sugar to have cyclic structure is
a. 3
b. 4
c. 5
d. 6
24. An aldo hexose will have _____ stereoisomers
a. 8
b. 10
c. 14
d. 16
25. Minimum number of carbon required for a monosaccharide
a. 1
b. 2
c. 3
d. 4
Learn more: Carbohydrates MCQ Part-2 | Part-3 |
Answers with Explanations
1. Ans. (a) (CH2O)n
Majority of carbohydrates follow this general formula
2. Ans. (b). Glyceraldehyde
3. Ans. (a). C12H22O11
4. Ans. (c). α 1 – 4
Maltose is a disaccharide of two glucose molecules linked by α 1 – 4 glycosidic linkage.
5. Ans. (a). 4
This can be calculated by a formula 2 n, where n will be the number of chiral carbon in the molecule. A keto pentose will have a total of five carbons, among which two carbons will be chiral.
Chiral carbon: An asymmetric carbon, i.e., the four valences of the carbon are satisfied by four different groups or atoms
6. Ans. (d). Starch
Laminarin: reserve food material of brown algae
Chrysolaminarin: reserve food material of diatoms
Floridian starch: reserve food material of red algae
7. Ans. (c). Dihydroxyacetone
All carbohydrates except dihydroxyacetone (a keto triose) will have at least one chiral centre.
8.Ans. (d). Erythrose
Erythrose is an aldo tetrose
Arabinose, Xylose and Lyxose are aldo pentoses
9. Ans. (c). Lyxose
10. Ans (d). Both (a) and (b)
Epimer: Two isomers that differs only in the configuration around a carbon atom.
11. Ans. (c). Glyceraldehyde
Glyceraldehyde is an aldose sugar
Xylulose, Dihydroxyacetone and Ribulose are ketose sugars
12. Ans. (a). Sucrose
Seliwanoff test is used to distinguish aldoses and ketoses. Ketoses give positive test for Seliwanoff test. Sucrose gives Seliwanoff test positive since it contains a fructose moiety which is a ketose sugar.
13. Ans. (a). Erythrulose
Xylulose is a keto pentose
Sorbose and Psicose are keto hexoses
14. Ans. (c). α 1 – 6
Isomaltose is a disaccharide of two glucose molecules connected by α 1 – 6 glycosidic linkage rather than the α-1 – 4 glycosidic linkage in maltose
15. Ans. (a). Vit. C
16. Ans (b). Xylitol
Xylitol, Ribitol, Inositol and Mannitol are sugar alcohols
17. Ans. (b). β 1 – 4
Cellobiose: a reducing disaccharide of glucose molecules connected by β 1 – 4 glycosidic linkage.
18. Ans. (d). Altrose
Altrose: is an aldo hexose sugar
Deoxyribose, Rhamnose and Fucoses are deoxysugars
19. Ans. (b). Proteins specific to sugars
20. Ans. (a). Dihydroxyacetone
21. Ans. (b). Glucose and glucose
22. Ans. (c). α 1 – 2
Sucrose is a non-reducing disaccharide of glucose and fructose connected by α 1 – 2 glycosidic linkage.
23. Ans. (c). 5
Aldose sugars with 4 carbons onwards can form cyclic structures
24. Ans. (d). 16
Use the formula 2 n, where n is the number of chiral carbon atoms. In aldo hexoses there will be four chiral carbons, thus 2 4 = 2 x 2 x 2 x 2 = 16. Of these 16 isomers 8 will be D form and the remaining 8 will be L form.
25. Ans. (c). 3
It is not possible to form a carbohydrate with 2 carbon atom. Simplest carbohydrates are with three carbon back bone and they are glyceraldehyde (an aldo triose) and dihydroxyacetone (a keto triose).
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