Q: Which of the following equations correctly represents the formation of a phosphodiester bond during RNA synthesis?

$$\text{NTP} + (RNA)_{n} \rightarrow (RNA)_{n+1} + 2\text{Pi}$$

Question 1

Which of the following statements best describes the difference between RNA and DNA nucleotides?

Accepted Answer

RNA nucleotides contain uracil instead of thymine, and ribose instead of deoxyribose.

Question 2

During transcription, which strand of DNA is used as the template for RNA synthesis, and what is the direction of RNA synthesis?

Accepted Answer

The template strand is used as the template, and RNA is synthesized in the 5' to 3' direction.

Question 3

Which of the following equations correctly represents the formation of a phosphodiester bond during RNA synthesis?

Accepted Answer

$$	ext{NTP} + (RNA)_{n} ightarrow (RNA)_{n+1} + 2	ext{Pi}$$

Question 4

Which type of RNA is directly translated into protein in eukaryotic cells?

Accepted Answer

Messenger RNA (mRNA)

Question 5

A mutation in the TATA box of a eukaryotic gene is most likely to affect which process?

Accepted Answer

The binding of RNA polymerase II and initiation of transcription

Question 6

Which of the following best explains why eukaryotic transcription is more complex than bacterial transcription?

Accepted Answer

Eukaryotic transcription involves multiple RNA polymerases, chromatin structure, and extensive RNA processing.

Question 7

Which of the following is NOT a function of the 5' cap added to eukaryotic pre-mRNA?

Accepted Answer

Initiation of polyadenylation at the 3' end

Question 8

A researcher finds a eukaryotic gene with two alternative polyadenylation sites and observes two different mRNA products in different tissues. Which mechanism best explains this observation?

Accepted Answer

Alternative polyadenylation

Question 9

Which of the following statements about introns is correct?

Accepted Answer

Introns are removed from pre-mRNA by the spliceosome in eukaryotes.

Question 10

Which of the following best describes the role of enhancer sequences in eukaryotic transcription?

Accepted Answer

They bind activator proteins and increase transcription by facilitating the assembly of the transcription complex.

Question 11

A patient has a mutation that prevents the methylation of the 5' cap of mRNA. Which of the following processes is most likely to be affected?

Accepted Answer

Transport of mRNA out of the nucleus

Question 12

Which of the following is a correct statement about the function of the carboxyl terminal domain (CTD) of RNA polymerase II?

Accepted Answer

It serves as a platform for the assembly of pre-mRNA processing machinery, coupling transcription and RNA processing.

Question 13

Which of the following equations best represents the process of polyadenylation?

Accepted Answer

$$(pre	ext{-}mRNA) + nATP ightarrow (mature\ mRNA) + nPP_i$$

Question 14

Which of the following is a real-world example of alternative splicing affecting protein function?

Accepted Answer

The human CT/CGRP gene produces calcitonin in thyroid cells and CGRP in neuronal cells due to alternative splicing and polyadenylation.

Question 15

Which of the following statements about RNA editing is correct?

Accepted Answer

RNA editing can involve the addition or deletion of uracil nucleotides, often guided by a gRNA.

Question 16

Which of the following best explains why eukaryotic mRNAs are generally more stable than bacterial mRNAs?

Accepted Answer

Eukaryotic mRNAs are protected by a 5' cap and a 3' poly-A tail.

Question 17

A mutation in a eukaryotic gene eliminates the branch point adenine in an intron. What is the most likely consequence?

Accepted Answer

The intron will not be removed, leading to abnormal mRNA and potentially nonfunctional protein.

Question 18

Which of the following is a key evolutionary insight from comparative transcription studies?

Accepted Answer

Archaeal transcription machinery is more similar to eukaryotic than to bacterial systems.

Molecular Biology of Transcription and RNA Processing: Study Notes CH8

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