$$\text{NTP} + \text{RNA}_{n} \rightarrow \text{RNA}_{n+1} + PP_i$$

Question 1

Which of the following best describes the Central Dogma of molecular biology as originally proposed by Crick?

Accepted Answer

Genetic information flows from DNA to RNA to protein.

Question 2

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

Accepted Answer

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

Question 3

Which of the following is NOT a function of the promoter region in a gene?

Accepted Answer

Coding for the protein product.

Question 4

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

Accepted Answer

DNA contains deoxyribose, while RNA contains ribose.

Question 5

Which base is present in RNA but absent in DNA?

Accepted Answer

Uracil (U)

Question 6

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

Accepted Answer

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

Question 7

Which of the following statements about RNA polymerase is TRUE?

Accepted Answer

RNA polymerase synthesizes RNA in the 5' to 3' direction without a primer.

Question 8

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

Accepted Answer

It directs RNA polymerase to the promoter region.

Question 9

Which consensus sequences are typically found in bacterial promoters?

Accepted Answer

$$-10$$ region: TATAAT and $$-35$$ region: TTGACA

Question 10

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

Accepted Answer

Eukaryotic genes are interrupted by introns and have larger promoter regions.

Question 11

Which modification is added to the 5' end of eukaryotic mRNA during processing?

Accepted Answer

A 7-methyl-guanosine cap

Question 12

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

Accepted Answer

It protects the transcript from exonuclease digestion and aids in export from the nucleus.

Question 13

Which of the following statements about alternative splicing is TRUE?

Accepted Answer

Alternative splicing allows a single gene to encode multiple proteins.

Question 14

Which enzyme is responsible for removing introns from eukaryotic pre-mRNA?

Accepted Answer

Spliceosome

Question 15

Which of the following equations represents the relationship between the number of genes and genome size in humans?

Accepted Answer

$$	ext{Genome size} \approx 3,200 	ext{Mb}$$, $$	ext{Number of genes} \approx 25,000$$

Question 16

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

Accepted Answer

Transcription and translation are coupled in prokaryotes, but separated in eukaryotes.

Question 17

Which of the following is required for transcription initiation in eukaryotes but not in prokaryotes?

Accepted Answer

General Transcription Factors (GTFs)

Question 18

Which of the following best describes the function of topoisomerase during transcription?

Accepted Answer

It prevents overwinding of DNA ahead of the RNA polymerase.

Question 19

Which of the following is a plausible consequence of a mutation in the consensus sequence of a bacterial promoter?

Accepted Answer

Sigma factor may not recognize the promoter, reducing transcription initiation.

Transcription: DNA to RNA in Prokaryotes and Eukaryotes

Study Guide - Practice Questions