Question 1

Which of the following best describes the Central Dogma of molecular biology?

Accepted Answer

Information flows from DNA to RNA to protein.

Question 2

Which sugar is found in RNA but not in DNA, and what is the key structural difference?

Accepted Answer

Ribose; it has a hydroxyl group at the 2' carbon.

Question 3

During transcription, which strand of DNA is used as the template for RNA synthesis, and in which direction does RNA polymerase move along this strand?

Accepted Answer

The template strand; 3' to 5' direction.

Question 4

Which of the following modifications occur to eukaryotic pre-mRNA before it becomes mature mRNA?

Accepted Answer

Addition of a 5' cap, addition of a poly-A tail, and removal of introns.

Question 5

What is the function of the promoter region in a gene?

Accepted Answer

It is the site where RNA polymerase and transcription factors bind to initiate transcription.

Question 6

Which of the following statements about prokaryotic transcription is correct?

Accepted Answer

The primary transcript is immediately ready for translation.

Question 7

Which base is found in RNA but not in DNA, and what does it replace?

Accepted Answer

Uracil; it replaces thymine.

Question 8

What is the role of the spliceosome in eukaryotic cells?

Accepted Answer

It removes introns from the pre-mRNA.

Question 9

A mutation in the polyadenylation signal of a gene would most likely affect which process?

Accepted Answer

Termination and export of mRNA from the nucleus

Question 10

Which of the following best explains why RNA is considered less stable than DNA?

Accepted Answer

RNA contains a hydroxyl group at the 2' carbon, making it more susceptible to hydrolysis.

Question 11

Which of the following is a direct result of alternative splicing in eukaryotes?

Accepted Answer

Production of different protein products from the same gene

Question 12

During the elongation phase of transcription, what provides the energy for the addition of each ribonucleotide to the growing RNA strand?

Accepted Answer

Cleavage of the high-energy phosphate bond in the incoming ribonucleoside triphosphate

Question 13

In eukaryotic transcription, what is the function of enhancer sequences?

Accepted Answer

They bind transcriptional activator proteins to increase the rate of transcription.

Question 14

A scientist discovers a new organism whose mRNA is not modified after transcription. Where is transcription most likely occurring in this organism?

Accepted Answer

In the cytoplasm of a prokaryotic cell

Question 15

Which of the following equations correctly represents the polymerization reaction during RNA synthesis?

Accepted Answer

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

Question 16

Which of the following best explains why the 5' cap and poly-A tail are important for eukaryotic mRNA?

Accepted Answer

They protect mRNA from degradation and help with ribosome recognition.

Question 17

A mutation that prevents the binding of general transcription factors to the promoter would most likely result in which of the following?

Accepted Answer

Failure to initiate transcription

Question 18

Which of the following statements about the directionality of nucleic acid synthesis is correct?

Accepted Answer

Both DNA and RNA are synthesized in the 5' to 3' direction.

Question 19

Which of the following is a key difference between transcription in prokaryotes and eukaryotes?

Accepted Answer

In eukaryotes, transcription and translation are separated by the nuclear envelope.

Nucleic Acids and Transcription: Structure, Function, and Regulation

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