Biology Multiple Choice Questions and Answers for Different Competitive Exams

Multiple Choice Questions on Biomolecules

1. In double helix of DNA, the two strands are
a) coiled around a common axis
b) coiled differently
c) coiled over protein sheath
d) coiled around each other

2. Living cell contains 60-95% water. Water present in human body is
a) 60-65%
b) 70-75%
c) 65-70%
d) 75-80%

3. Nucleotides are building blocks of nucleic acids. Each nucleotide is a composite molecule formed by
a) base- sugar- phosphate
b) base- sugar- OH
c) sugar-phosphate
d) (base sugar phosphate)n

4. The major role of minor elements inside living organisms is to act as
a) Co factors of enzymes
b) Binder of cell structure
c) Constituent of hormones
d) Building blocks of important amino acids

5. Lipids are insoluble in water because lipid molecules are
a) Hydrophilic
b) Neutral
c) Zwitter ions
d) Hydrophobic

6. ATP is
a) vitamin
b) Enzyme
c) Nucleic acid
d) Nucleotide

7. Which of the following have carbohydrate as prosthetic group
a) Glycoprotein
b) Lipoprotein
c) Nucleoprotein
d) Chromoprotein

8. Lactose is composed of
Lactose: reducing sugar
a) glucose + galactose
b) fructose+ galactose
c) glucose + fructose
d) glucose + glucose

9. In which of the following groups are all polysaccharides?
a) Sucrose, glucose and fructose
b) Maltose, lactose and fructose
c) glycogen, sucrose and maltose
d) Glycogen, cellulose and starch

10. Amino acids are produced from
a) Proteins
b) Fatty acids
c) Essential oils
d) α-keto acids

11. In RNA, thymine is replaced by
a) adenine
b) guanine
c) cytosine
d) uracil

12. Which purine base is found in RNA?
a) Thymine
b) Uracil
c) Cytosine
d) Guanine

13. Which of the following nucleotide sequences contains four pyrimidine bases?
a) GATCAATGC
b)UAGCGGUAA
c) GCUAGACAA
d) both b and c

14. Cellulose, the most important constituent of plant cell wall is made up of
cellulose
a) Branched of glucose molecules linked by β-1, 4 glycosidic bond in straight chain and α-1,6 glycosidic bond at the site of branching
b) Unbrached chain of glucose molecules linked by β--1,4 glycosidic bond
c) Branched chain of glucose molecules linked by β-1, 4 glycosidic bond
d) Branched chain of glucose molecules linked by β-1, 4 glycosidic bond in straight chain and α-1,6 glycosidic bond at the site of branching

15. Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all of these
a) Enhance oxidative metabolism
b) Help in regulating metabolism
c) are conjugated proteins
d) are exclusively synthesised in the body of a living organism as at present
Free Online MCQ Test On:

 Biomolecules -> Biomacromolecules -> Proteins -> Carbohydrates -> Lipids 
Answers
1.  a) coiled around a common axis
2. c) 65-70%
3. a) base- sugar- phosphate
4. a) Co factors of enzymes
5. d) Hydrophobic
6. d) Nucleotide
7. a) Glycoprotein
8. a) glucose + galactose
9. d) Glycogen, cellulose and starch
10. a) Proteins
11. d) uracil
12. d) Guanine
13. a) GATCAATGC
14. b) Unbrached chain of glucose molecules linked by β--1,4 glycosidic bond
15. b) Help in regulating metabolism

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