NCERT Class 12 Biology: Chapter – 6 Molecular Basis of Inheritance Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 19:

Which of the following are the functions of RNA?

a. It is a carrier of genetic information from DNA to ribosomes synthesising polypeptides.

b. It carries amino acids to ribosomes.

c. It is a constituent component of ribosomes.

d. All of the above.

Answer: (d)

Question 20:

While analysing the DNA of an organism a total number of 5386 nucleotides were found out of which the proportion of different bases were: Adenine Guanine , Cytosine , Thymine . Considering the Chargaff՚s rule it can be concluded that: a. it is a double stranded circular DNA

b. It is single stranded DNA

c. It is a double stranded linear DNA

d. No conclusion can be drawn

Answer: (b)

Question 21:

In some viruses, DNA is synthesised by using RNA as template. Such a DNA is called:

a. A-DNA

b. B-DNA

c. c DNA

d. r DNA

Answer: (c)

Question 22:

If Meselson and Stahl՚s experiment is continued for four generations in bacteria, the ratio of containing DNA in the fourth generation would be:

a. 1: 1: 0

b. 1: 4: 0

c. 0: 1: 3

d. 0: 1: 7

Answer: (d)

Question 23:

If the sequence of nitrogen bases of the coding strand of DNA in a transcription unit is:

, the sequence of bases in its RNA transcript would be;

Answer: (a)

Question 24:

The RNA polymerase holoenzyme transcribes:

a. the promoter, structural gene and the terminator region

b. the promoter, and the

c. the structural gene and the terminator regions

d. the structural gene only.

Answer: (c)

Question 25:

If the base sequence of a codon in , the sequence of pairing with it must be:

Answer: (b)

Question 26:

The amino acid attaches to the at its:

d. DHU loop

Answer: (b)

Question 27:

To initiate translation, the mRNA first binds to:

a. The smaller ribosomal sub-unit,

b. The larger ribosomal sub-unit

c. The whole ribosome

d. No such specificity exists.

Answer: (a)