A classic biochemical experiment nicely illustrated the point that the ribosome recognizes tRNA and not the amino acid that it is carrying. In that following observation were made. Which of them can be correct.

A. The cysteine attached to cysteine-tRNACys can be converted to an alanine by chemical reduction to give alanine-tRNACys.

B. Alanine-tRNACys introduces alanines at codons that specify insertion of cysteine.

C. Different mechanism is used to incorporate selenocyteine on tRNA as selenocysteine is incorporated into proteins by chemical modification after translation

D. Selenocysteine is generated enzymatically from serine carried on a special tRNA that is charged by serine-tRNA synthetase

E. Above examples can conclude that the translation machinery relies on the high fidelity of the aminoacyl-tRNA synthetases to ensure the accurate decoding of each mRNA

#Question id: 4551

#Unit 3. Fundamental Processes

Various types of σ factor in column I, that are involved in several other function given in column II

 Which of the following combination is correct?

#Question id: 4552

#Unit 3. Fundamental Processes

The sequence of σ54 is distinctly different from that of all the σ70-like factors, some characteristics about σ54 is given below;

a) The σ54-RNA polymerase binds to the glnA promoter and immediately melt the DNA strands and initiate transcription

b) σ54-polymerase does not require ATP hydrolysis to separate the strands at a start site only require activator such as   NtrC

c) σ54-RNA polymerase initiate transcription of glnA promoter only when it is activated by NtrC

d) ATP hydrolysis is required for activation of bound σ54-RNA polymerase by phosphorylated NtrC

Which of the following from the bove combination is INCORRECT?

#Question id: 4553

#Unit 3. Fundamental Processes

The NtrC protein (nitrogen regulatory protein C)—stimulates transcription of the glnA gene, this protein is an activator of σ54-RNA polymerase. Which of the following given characteristics about this protein is incorrect?

#Question id: 4554

#Unit 3. Fundamental Processes

In which studies have shown that phosphorylated NtrC bound at enhancers and σ54-polymerase bound at the promoter interact directly, forming a loop in the DNA between the binding sites?

#Question id: 4555

#Unit 3. Fundamental Processes

The σ54-RNA polymerase binds to the glnA promoter but does not melt the DNA strands and initiate transcription until it is activated by

#Question id: 4557

#Unit 3. Fundamental Processes

In eukaryotic transcription RNA polymerase II is transcribed