Cytogenetics Practice Test 1

1. Rho dependent termination mechanism doesn’t reguire____________

G-C rich stem

Sigma factor

Stem loop structure

ATP

2. In an experiment you mutate the C terminal domain of alpha subunit of the RNA polymerase. What will you expect to see?

Transcription is at random sites

Transcription is less

Transcription is absent

Transcription is more

3. Which of these items have a positive impact on PEDCBA transcription?

Anti-Trp with TRAP

Trp-ANTI TRAP

Trp-TRAP

Anti-Trp with Trp-TRAP

4. In an experiment you add increasing amount of sigma factor to a mixture of DNA fragment and core polymerase in vitro. You also add [¹⁴C]ATP and [γ-³²P]ATP in the mixture and check the rate of incorporation. Results show that the incorporation of both of this labels increase on adding more sigma factor. What will you conclude from your observation?

Sigma increases initiation of transcription rate

Sigma causes faster elongation

Sigma increases initiation and elongation rate

Sigma confers specificity and increases transcription rate

5. In a mero-diploid you have one I- and one I+ Repressor gene in the two lac operons. I+ is wild type while I- is a mutant which produces a repressor that doesn’t bind. What would be the functionality of the diploid?

Will have impaired functioning

Function normally

Will be non-functional

May or may not function

6. If a bacteria is facing lack of carbon sources in the media, which sigma factor concentration is expected to increase?

Sigma S

Sigma 70

Sigma 32

Sigma E

7. Which of these interactions is the weakest?

rA-dT

rC-dG

rG-dC

rU-dA

8. A ssRNA shows inverted tandem repeat. What would be its secondary structure?

Stem-loop structure

Linear

Crucifix

Hair pin

9. Which cation is placed in the catalytic subunit of RNA polymerase?

Mg²⁺

Zn²⁺

Fe³⁺

Mn²⁺

10. Which of this subunit is not a part of core DNA polymerase?

Beta

Theta

Alpha

Eta