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’

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

Haploids are more suitable for mutation studies than the diploids. This is because

(1) haploids are reproductively more stable than diploids

(2) mutagenes penetrate in haploids more effectively than is diploids

(3) haploids are more abundant in nature than diploids

(4) all mutations, whether dominant or recessive are expressed in haploids

Telomere repetitive DNA sequences control the function of eukaryotic chromosomes because they:

(1) act as replicons

(2) are RNA transcription initiator

(3) help chromosome pairing

(4) prevent chromosome loss

Molecular basis of organ differentiation depends on the modulation in transcription by:

(1) RNA polymerase

(2) ribosome

(3) transcription factor

(4) anticodon

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

During transcription RNA polymerase holoenzyme binds to a gene promoter and assumes a saddle-like structure. What is it’s DNA-binding sequence?

(1) TTAA

(2) AATT

(3) CACC

(4) TATA