Molecular Basis of Inheritance MCQs for NEET — Botany Questions with Answers

In dsDNA, A = T and G = C

A + T / G + C = 0.3

2A/2G = 0.3

A = 0.3 X G ----(i)

Also, (A + T) + (G + C) = 100 ---(ii)

Substituting all amino acids in terms of G :-

0.3G + 0.3G + G + G = 100

2.6G = 100

G = 38.5 = C

From (i)

A = T = 0.3G = 11.55

A + G / T + C = 11.55 + 38.5 / 38.5 + 11.55 = 1

RNA polymerase is the main enzyme for RNA synthesis in transcription.

The key differences between mRNA and tRNA are: B) tRNA has a more elaborated 3D structure due to extensive base pairing, and C) tRNA is smaller than mRNA. mRNA does not bear an anticodon, and tRNA has anticodons, not codons. Therefore, the correct option is o3.

Gene expression results in the formation of a polypeptide which in eukaryotes is regulated at following levels:

(i) transcriptional level (formation of primary transcript)

(ii) processing level (regulation of splicing)

(iii) transport of mRNA from nucleus to the cytoplasm

(iv) translational level.

(page-115)

In prokaryotes, control of the rate of transcriptional initiation is the predominant site for control of gene expression.

In a transcription unit, the activity of RNA polymerase at a given promoter is in turn regulated by interaction with accessory proteins.

(page-116)

All of the above mentioned statements are correct.

A. Transcription in prokaryotes is catalysed by RNA Polymerase only.

B. In eukaryotes,

RNA polymerase I : transcribes rRNAs (28S, 18S, and 5.8S)

RNA polymerase III : transcription of tRNA, 5srRNA, and snRNAs

C. RNA polymerase II : precursor of mRNA, the heterogeneous nuclear RNA (hnRNA).

D.   Large subunit of Ribosome has three sites- E, P and A site

Genetic code is universal in living organisms and this proves that all organisms are evolutionarily related as all contains amino acids composed of 61 universal code.

(page-112)

All the statements are correct except:-
II. The ribosome consists of structural RNAs and 80 different proteins.In its inactive state, it exists as two subunits; a large subunit and a small subunit.
V. Complexes composed of an amino acid linked to tRNA bind to the appropriate codon in mRNA by forming complementary base pairs with the tRNA anticodon. The ribosome moves from codon to codon along the mRNA. Amino acids are added one by one, translated into Polypeptide sequences.
VI. The newly formed polypeptide undergoes post-translational modifications.
(page-115)

According to Watson and Crick model of DNA, DNA exists as a double helix.

The two chains are coiled in a right-handed fashion. There are roughly 10

Base pairs in each turn so length of DNA with 45000 bp will take 4500

turns in a DNA molecule.

(page-98)

One of goals of HGP is to address the ethical, legal, and social issues (ELSI) that may arise from the project.

(page-118)