Biomolecules — Page 3 | NEET Chemistry

Q21

The nitrogenous organic base purine occurring in RNA is

A cytosine

B thymine

C guanine

D uracil

Correct Answer

Option C

Solution

(c) Purines in RNA are adenine and guanine.

Q22

One of the similarities between DNA and RNA is that both

A are polymers of nucleotides

B are capable of replicating

C have similar sugars

D have similar pyrimidine bases

Correct Answer

Option A

Solution

(a) DNA and RNA are both polymers of nucleotides.

Q23

A nucleotide is formed of

A Purine, pyrimidine and phosphate

B Purine, sugar and phosphate

C Nitrogen base, sugar and phosphate

D Pyrimidine, sugar and phosphate

Correct Answer

Option C

Solution

(c) Each nucleotide comprises nitrogenous bases, pentose sugar and phosphoric acid.

Q24

Which one of the following hydrolyses internal phosphodiester bonds in a polynucleotide chain?

A Lipase

B Protease

C Endonuclease

D Exonuclease

Correct Answer

Option C

Solution

(c) Endonucleases hydrolyse internal phosphodiester bonds while exonucleases hydrolyse terminal bonds.

Q25

Length of one turn of the helix in B-form DNA is approximately

A 3.4 nm

B 2 nm

C 0.34 nm

D 20 nm

Correct Answer

Option A

Solution

(a) Length of one turn of the DNA helix is 34 A = 3.4 nm.

Q26

Purines found both in DNA and RNA are:

A Adenine and thymine

B Adenine and guanine

C Guanine and cytosine

D Cytosine and thymine

Correct Answer

Option B

Solution

(b) Purines adenine and guanine are found both in DNA and RNA.

Q27

Lipids are insoluble in water because lipid molecules are

A hydrophilic

B hydrophobic

C neutral

D zwitter ions

Correct Answer

Option B

Solution

(b) Lipids are insoluble in water because they are hydrophobic.

Q28

A typical fat molecule is made up of

A three glycerol molecules and one fatty acid molecule

B one glycerol and three fatty acid molecules

C one glycerol and one fatty acid molecule

D three glycerol and three fatty acid molecules

Correct Answer

Option B

Solution

(b) A typical fat molecule has one glycerol and three fatty acid molecules.

Q29

Which one of the following is the most abundant protein in the animals?

A Collagen

B Lectin

C Insulin

D Haemoglobin

Correct Answer

Option A

Solution

(a) Collagen is the most abundant protein in animal world.

Q30

Water present in human body is

A 60-65%

B 50-55%

C 75-80%

D 65-70%

Correct Answer

Option D

Solution

(d) About 65-70% of human body is water.