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

$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$$

Question 1

Which of the following is a chemical difference between DNA and RNA?

Accepted Answer

RNA contains uracil, while DNA contains thymine.

Question 2

During RNA synthesis, which enzyme catalyzes the formation of the phosphodiester bond?

Accepted Answer

RNA polymerase

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

The central dogma of molecular biology describes the flow of genetic information as:

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 5

Which of the following best explains why mRNA is considered an 'unstable' RNA molecule?

Accepted Answer

It is rapidly degraded after translation.

Question 6

In a pulse-chase experiment using radioactive uracil, what does the rapid dissipation of radioactivity from the cytoplasm indicate?

Accepted Answer

Newly synthesized RNA is quickly degraded after translation.

Question 7

Which strand of DNA has the same sequence as the RNA transcript (except for uracil replacing thymine)?

Accepted Answer

Coding strand

Question 8

Which of the following types of RNA is directly involved in the translation of genetic information into protein?

Accepted Answer

mRNA, rRNA, and tRNA

Question 9

Which of the following best describes the function of microRNAs (miRNAs) in gene regulation?

Accepted Answer

They bind to the 3' untranslated region of mRNA and inhibit translation or promote degradation.

Question 10

A mutation in the gene encoding PIWI proteins would most likely affect which cellular process?

Accepted Answer

Silencing of transposable elements in the germline

Question 11

Which of the following is a function of small nuclear RNAs (snRNAs)?

Accepted Answer

They are required for the correct splicing of pre-mRNA.

Question 12

Which of the following long non-coding RNAs is responsible for X-chromosome inactivation in mammals?

Accepted Answer

XIST

Question 13

Which of the following best describes the role of rRNA in eukaryotic cells?

Accepted Answer

It forms the catalytic core of ribosomes and facilitates protein synthesis.

Question 14

A patient is found to have a mutation that prevents the removal of introns from pre-mRNA. Which RNA molecule is most likely defective?

Accepted Answer

snRNA

Question 15

Which of the following statements about the directionality of transcription is correct?

Accepted Answer

RNA is synthesized in the 5' to 3' direction.

Question 16

Which of the following best explains why only mRNA is translated into protein?

Accepted Answer

mRNA contains codons that are read by the ribosome during translation.

Question 17

A new drug inhibits the removal of the poly-A tail from mRNA. What is the most likely effect on gene expression?

Accepted Answer

Increased stability and translation of mRNA.

Question 18

Which of the following is a real-world application of microRNA-based therapeutics?

Accepted Answer

AMT-130 for Huntington Disease

Question 19

Which of the following best describes the function of the seed region in microRNAs?

Accepted Answer

It determines the specificity of mRNA binding and gene silencing.

Question 20

Which of the following best explains the role of PIWI-interacting RNAs (piRNAs) in genome stability?

Accepted Answer

They silence transposable elements by recruiting DNA methyltransferases.

The Biochemistry of RNA Synthesis and RNA Classification

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