Biochemistry Multiple Choice Questions on “Monosaccharides and Disaccharides”.
1. Anthrone method is preferred in the determination of ___________
A. Carbohydrates
B. Proteins
C. Vitamins
D. Fats
Answer: A
Clarification: Carbohydrates are dehydrated with con.H2SO4 to form Furfural, which condenses with anthrone to form a green color.
2. Which of the following is an example of epimers?
A. Glucose & Galactose
B. Glucose & Ribose
C. Mannose & Glucose
D. Galactose & Mannose
Answer: A
Clarification: Both glucose and galactose have the same chemical formula but the orientation of –OH group on C4 molecule in both the compounds are different.
3. Which of the following has reducing properties?
A. Glucuronic acid
B. Gluconic acid
C. Glucaric acid
D. Mucic acid
Answer: A
Clarification: Glucuronic acid has a free aldehyde group which is responsible for reducing property.
4. The red precipitate formed when glucose is heated with “Benedict’s reagent” is ___________
A. Cupric hydroxide
B. Cuprous hydroxide
C. Cupric oxide
D. Cuprous oxide
Answer: D
Clarification: When reducing sugars are heated in the presence of an alkali and reduce the Cupric compounds present in the Benedict’s reagent to cuprous compounds which get precipitated as insoluble red Cu2O.
5. Fructose and Glucose can be distinguished by ___________
A. Selwinoff’s reagent
B. Benedict’s reagent
C. Fehling’s reagent
D. Barfoed’s reagent
Answer: A
Clarification: Selwinoff’s reagent gives positive test for fructose.
6. Which of the following is an example of monosaccharide?
A. Galactose
B. Sucrose
C. Lactose
D. Maltose
Answer: A
Clarification: Galactose is a simple sugar that consists of a single polyhydroxy aldehyde.
7. Which of the following is an example of disaccharide?
A. Glucose
B. Fructose
C. Galactose
D. Maltose
Answer: D
Clarification: Maltose is a disaccharide with two monosaccharide glucose units.
8. In maltose, between which of the following carbons there is a linkage?
A. C1, C2
B. C2, C3
C. C1, C4
D. C2, C4
Answer: C
Clarification: Maltose contains two D-glucose residues joined by a glycosidic linkage between C1 of one glucose residue and C4 of the other.
9. Which of the following carbohydrates is a triose?
A. Glucose
B. Ribose
C. Ribulose
D. Glyceraldehyde
Answer: D
Clarification: Glyceraldehyde is a triose containing 3 carbons.
10. Lactose is a disaccharide of which of the following sugar units?
A. Glucose and fructose
B. Glucose and galactose
C. Glucose and sucrose
D. Glucose and ribose
Answer: B
Clarification: Lactose is a disaccharide of glucose and galactose.
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