Question 1

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

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

What is the main chemical difference between the sugars in DNA and RNA?

Accepted Answer

DNA contains deoxyribose, which lacks an OH group at the 2' carbon, while RNA contains ribose, which has an OH group at the 2' carbon.

Question 3

Which base is found in RNA but not in DNA?

Accepted Answer

Uracil

Question 4

During transcription, which DNA strand is used as the template for RNA synthesis?

Accepted Answer

The template strand, which is complementary to the RNA transcript.

Question 5

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

Accepted Answer

It signals the termination of transcription.

Question 6

In prokaryotes, what is the role of the sigma factor in transcription initiation?

Accepted Answer

It directs RNA polymerase to the promoter region of the gene.

Question 7

Which of the following sequences is most likely to be found at the -10 region of a bacterial promoter?

Accepted Answer

$$	ext{TATAAT}$$

Question 8

What is the function of the polyA tail added to eukaryotic mRNA?

Accepted Answer

It protects the mRNA from degradation and aids in export from the nucleus.

Question 9

Which of the following statements about RNA polymerase is TRUE?

Accepted Answer

RNA polymerase synthesizes RNA in the 5' to 3' direction and does not require a primer.

Question 10

A mutation in the consensus sequence of the -35 region of a bacterial promoter would most likely result in:

Accepted Answer

Reduced binding of RNA polymerase and decreased transcription initiation.

Question 11

Which of the following best explains why eukaryotic genes are generally larger and more complex than prokaryotic genes?

Accepted Answer

Eukaryotic genes contain introns and extensive regulatory regions.

Question 12

Which of the following is a correct pairing of RNA polymerase and its primary product in eukaryotes?

Accepted Answer

RNA polymerase II – mRNA

Question 13

During transcription elongation in prokaryotes, what happens to the sigma factor?

Accepted Answer

It dissociates from the core RNA polymerase after about 9 nucleotides are added.

Question 14

Which of the following modifications occurs to eukaryotic pre-mRNA before it is exported from the nucleus?

Accepted Answer

Addition of a 5' cap, splicing of introns, and addition of a polyA tail.

Question 15

Which of the following best describes the function of tRNA during translation?

Accepted Answer

It brings amino acids to the ribosome and matches them to the mRNA codons.

Question 16

A gene is defined as:

Accepted Answer

A sequence of DNA that encodes a functional product, usually a protein.

Question 17

Which of the following is a consequence of alternative splicing in eukaryotes?

Accepted Answer

A single gene can produce multiple protein isoforms.

Question 18

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

Accepted Answer

RNA is synthesized in the 5' to 3' direction, using the 3' to 5' DNA template strand.

Question 19

Which of the following best explains why only one strand of DNA is used as a template during transcription?

Accepted Answer

The template strand provides the complementary sequence needed to synthesize the correct RNA transcript.

Transcription: DNA to RNA – Molecular Basis and Mechanisms

Study Guide - Practice Questions