Select the two statements out of the four (A - D) given below about lac operon.

(A) Glucose or galactose may bind with the repressor and inactivate it

(B) In the absence of lactose, the repressor binds with the operator region

(C) The z-gene codes for permease

(D) This was elucidated by Francois Jacob and Jacques Monod

The correct statements are

1. (B) and (C)

2. (A) and (C)

3. (B) and (D)

4. (A) and (B)

In the DNA molecule

(1) the total amount of purine nucleotides and pyrimidine nucleotides is not always equal

(2) there are two strands, which run parallel in the 5’ → 3’direction

(3) the proportion of adenine in relation to thymine varies with the organism

(4) there are two strands, which run antiparallel-one in 5’ → 3’ direction and other in 3’ → 5’

Which one of the following pairs of codons are correctly matched with their function or the signal for the particular amino acid?

1. GUU, GCU – Alanine

2. UAG, UGA – Stop

3. AUG, ACG – Start/methionine

4. UUA, UCA – Leucine

The length of DNA molecule greatly exceeds the dimensions of the nucleus in eukaryotic cells. How is this DNA accommodated?

(1) Deletion of non essential genes

(2) Super-coiling in nucleosomes

(3) DNAse digestion

(4) Through elimination of repetitive DNA

Differentiation of organs and tissues in a developing organism, is associated with:

(1) developmental mutations

(2) differential expression of genes

(3) lethal mutations

(4) deletion of gens

Amino acid sequence, in protein synthesis is decided by the sequence of

(1) t-RNA

(2) m-RNA

(3) c-DNA

(4) r-RNA

One turn of the helix in a B-form DNA is approximately:

(1) 20 nm

(2) 0.34 nm

(3) 3.4 nm

(4) 2 nm

Antiparallel strands of a DNA molecule means that:

(1) one strand turns anti-clockwise

(2) the phosphate groups of two DNA strands, at their ends, share the same position

(3) the phosphate groups at the start of two DNA strands are in opposite position (pole)

(4) one strand turns clockwise

Complete genomic sequence of the following plant has been recently announced is

(1) Arabidopsis thaliana

(2) Tritium vulgare

(3) Cucurbita pepo

(4) Pisum sativum

Transcription in case of eukaryotes takes place in

(1) nucleus

(2) nucleolus

(3) cytoplasm

(4) ribosome