Question

1. Dimeric, unidirectional, multi-component, multi-enzyme complex. These features best describe which of the following:

a. Prokaryotic ribosome

b. DNA Polymerase holoenzyme

c. RNA Polymerase

d. Ligase

e. Amino-acyl transferase.

2. Which of the following is not a feature of bacterial DNA/chromosome?

a) DNA is non-linear (i.e. circular)

b) DNA strands are antiparallel and complementary.

c) DNA is coiled around histones.

d) DNA forms loop domains for organization.

e) DNA is supercoiled by topoisomerases.

3. The function of ssDNA Binding Proteins in prokaryotes is to ---------

a) Maintain separation of individual strands of the replication fork during DNA replication.

b) Provide a proof-reading function to prevent mutation.

c) Serve as recognition site for DNA Polymerase 1 and DNA Ligase after replication.

d) Cleave phosphor-diester bonds between nucleotides to relieve coiling stress during replication.

e) Maintain the open complex during transcription.

4. Which of the following is not a transcription product in bacteria?

a) Messenger RNA.

b) Polypeptides.

c) Pre-mRNA (unprocessed)

d) tRNA

e) Ribosomal RNA.

5. Which of the following statements about gene expression of prokaryotes and eukaryotes is erroneous?

a) Transcription and translation are physically separated in the eukaryotic cell, but not in prokaryotes.

b) Transcription product can be immediately transcribed by ribosomes in eukaryotes but not in prokaryotes.

c) Messenger RNA in eukaryotes includes introns, but does not include them in prokaryote mRNA.

d) Poly-adenine 'tails' are placed on the 3' end of the eukaryotic gene transcripts prior to translation. Prokaryotes have no such poly-adenine additions.

e) None of the above.

6. The consensus sequence 3'TTTACA5' at position -35 of the promoter region of a gene (DNA) fulfills which of the following roles?

a) oriC site for initiation of DNA replication.

b) Site of RNA Polymerase recognition during transcription.

c) Will yield the first two codons of gene transcript.

d) Recognition site for ribosome 30S subunit during translation.

e) None of the above.

Answer 1

Q 1. Ans: DNA polymerase holoenzyme

Q 2. Ans: c)- because bacteria do not have histones.

Q 3. Ans: a) Maintain separation of individual strands of the replication fork during DNA replication.

Q 4. Ans: b) Polypeptides.

Q 5. b) Transcription product can be immediately transcribed by ribosomes in eukaryotes but not in prokaryotes.

Q 6. Ans: b) Site of RNA Polymerase recognition during transcription.