What are those structures that appear as ‘beads-on-string’ in the chromosomes when viewed under electron microscope?

(1) Nucleotides

(2) Nucleosomes

(3) Base pairs

(4) Genes

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)

The one aspect which is not a salient feature of genetic code, is its being

(1) degenerate

(2) ambiguous

(3) universal

(4) specific

Satellite DNA is useful tool in

(1) organ transplantation

(2) sex determination

(3) forensic science

(4) genetic engineering

Which one of the following does not follow the central dogma of molecular biology?

(1) Pea

(2) Mucor

(3) Chlamydomonas

(4) HIV

Point mutation involves

(1) insertion

(2) change in single base pair

(3) duplication

(4) deletion

Whose experiments cracked the DNA and discovered unequivocally that a genetic code is a triplet?

(1) Nirenberg and Mathaei

(2) Hershey and chase

(3) Morgan and Sturtevant

(4) Beadle and Tatum

Semi-conservative replication of DNA was first demonstrated in

(1) Drosophila melanogaster

(2) Escherichia coli

(3) Streptococcus pneumoniae

(4) Salmonella typhimurium

What is not true for genetic code?

1. A codon in mRNA is read in a non-contiguous fashion

2. It is nearly universal

3. It is degenerate

4. It is unambiguous

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’