Question

1. Which of the following statements is TRUE regarding transcription in Eukaryotes?

pre-mRNAs are most susceptible to degradation in the nucleus after addition of the poly(A) tail

The template strand of DNA is utilized by RNA polymerase II to transcribe a gene

The entire mRNA molecule produced during transcription is ultimately translated into protein

dNTPs are utilized by RNA polymerase II during the elongation phase of transcription

Mutations in the Kozak sequence will result in inability of RNA polymerase II to bind to DNA

2. Which of the following mutations is LEAST likely to prevent transcription?

A mutation in the DNA-binding site of sigma factor

A mutation in the lacI gene that results in inability of allolactose to bind to the repressor

A mutation in the TATA box sequence of the gene

A mutation that prevents addition of 7-methylguanine to pre-mRNA

A mutation in the -10 consensus sequence of the Pribnow box

Answer 1

Ans-1- when the RNA is synthesized by RNA polymerase then in RNA Kozak sequence are present. These Kozak sequence helps in binding of ribosomes for translation. So mutation is Kozak sequence affects translation not transcription. Degradation of mRNA is prevented by poly A tail addition. Not entire region of mRNA is translated into protein. This is the template strand of DNA that is used by RNA polymerase to make RNA.

So option B is correct.

Ans-2- once the mRNA is synthesized the methyl cap is added at the 5' end of mRNA. If there is mutation in the site than capping will not occur but transcription is already done to make RNA.

So option D is correct.