NCERT Class 12 Biology: Chapter – 6 Molecular Basis of Inheritance Part 1 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Multiple Choice Questions

Question 1:

In a DNA strand the nucleotides are linked together by:

a. Glycosidic bonds

b. Phosphodiester bonds

c. Peptide bonds

d. Hydrogen bonds

Answer: (b)

Question 2:

A nucleoside differs from a nucleotide. It lacks the:

a. Base

b. Sugar

c. Phosphate group

d. Hydroxyl group

Answer: (c)

Question 3:

Both deoxyribose and ribose belong to a class of sugars called:

a. Trioses

b. Hexoses

c. Pentose՚s

d. Polysaccharides

Answer: (c)

Question 4:

The fact that a purine base always paired through hydrogen bonds with a pyrimidine base leads to, in the DNA double helix:

a. the antiparallel nature

b. the semiconservative nature

c. uniform width throughout DNA

d. uniform length in all DNA

Answer: (c)

Question 5:

The net electric charge on DNA and histones is:

a. both positive

b. both negative

c. negative and positive, respectively

d. zero

Answer: (c)

Question 6:

The promoter site and the terminator site for transcription are located at:

a. 3 ‘ (downstream) end and 5’ (upstream) end, respectively of the transcription unit

b. 5 ‘ (upstream) end and 3’ (downstream) end, respectively of the transcription unit

c. the 5՚ (upstream) end

d. the 3՚ (downstream) end

Answer: (b)

Question 7:

Which of the following statements is the most appropriate for sickle cell anaemia?

a. It cannot be treated with iron supplements

b. It is a molecular disease

c. It confers resistance to acquiring malaria

d. All of the above

Answer: (d)

Question 8:

One of the following is true with respect to AUG

a. It codes for methionine only

b. It is also an initiation codon

c. It codes for methionine in both prokaryotes and eukaryotes

d. All of the above

Answer: (d)

Question 9:

The first genetic material could be:

a. protein

b. carbohydrates

c. DNA

d. RNA

Answer: (d)