1. Which of the following distinguishes the sequences and function of prokaryoti

Question

1. Which of the following distinguishes the sequences and function of prokaryotic from eukaryotic promoters?

Only prokaryotic promoters contain conserved sequences

Only eukaryotic promoters contain conserved sequences

Only in eukaryotes are accessory proteins required for binding of RNA polymerase

Only in prokaryotes are accessory proteins required for binding of RNA polymerase

None of the above

Answers (1) and (4)

Answers (2) and (3)

2. Amongst RNAs, which of the following RNA types found in cells are relatively unstable?

mRNA

rRNA

tRNA

snRNA

All are equally unstable

Answers (2) and 3)

Answers (2), (3), and (4)

3. What is relationship between poly (A) tail length and mRNA translation in eukaryotes?

There is no relationship

Poly (A) tails are involved in binding of mRNA to the tRNAs

Long poly (A) tails impart shortened translation to mRNAs

Long poly (A) tails impart lengthened translation to mRNAs

There are no poly (A) tails in eukaryotic mRNAs, they are only in prokaryotic mRNAs

4. Small nuclear RNAs (snRNAs) play a role in which of the following processes?

DNA replication functioning as primers

RNA synthesis functioning as transcription initiation factors

RNA processing functioning as catalysts of intron removal

Translation by linking the mRNA with the ribosome

Addition of the 5’-7-methylguanine (CAP)

5. What is the role of sigma protein in mRNA synthesis in prokaryotes?

Forms the primer for mRNA synthesis

Termination of mRNA synthesis

Binding of RNA polymerase to promoters

Forming stem-loop structures in mRNA

Degradation of mRNA

Protection of mRNA from degradation

None of the above, sigma protein has no role in mRNA synthesis

Explanation / Answer

1. The correct option is None of the above

Both the prokaryotes and eukaryotes contain conserved sequences, and need accessory proteins for RNA polymerase binding.

2. The correct answer is mRNA

mRNA is the most unstable type of RNA in a cell. In bacteria, the mRNA has a half-life of only a few minutes.

3. The correct answer is There is no relationship

There is no relationship between poly (A) tail length and mRNA translation in eukaryotes. Poly A tail is added to the 3’end of the pre mRNA and protects the mRNA from enzymatic degradation, and also helps in the export of mature mRNA to the cytoplasm. Apart from this, the poly A tail length does nothing in mRNA translation.

4. The correct option is RNA processing functioning as catalysts of intron removal

A small nuclear RNA (snRNA) is one of many small RNA species that are found in nucleus; they are mainly involved in splicing or other RNA processing mechanisms.

5. Sigma protein allows the RNA polymerase to bind to the promoter. Once bound and initiates the transcription, the sigma protein is detached from the RNA polymerase.

Hence, the correct option is Binding of RNA polymerase to promoters.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.