Question 1

According to the central dogma of molecular biology, what is the correct flow of genetic information in a cell?

Accepted Answer

DNA → RNA → Protein

Question 2

Which enzyme is responsible for synthesizing RNA during transcription, and what is a key difference between this enzyme and DNA polymerase?

Accepted Answer

RNA polymerase; it does not require a primer to initiate synthesis

Question 3

During transcription, which DNA strand has the same sequence as the resulting mRNA (except for uracil replacing thymine)?

Accepted Answer

Coding strand

Question 4

A gene is best defined as:

Accepted Answer

A sequence of DNA that encodes a product like an RNA or a protein

Question 5

Which of the following processes occurs in eukaryotic gene expression but not in prokaryotic gene expression?

Accepted Answer

A cap is added to the 5′ end of the mRNA

Question 6

What is the function of the poly-A tail added to eukaryotic mRNA during RNA processing?

Accepted Answer

It protects the mRNA from degradation

Question 7

Which type of RNA carries amino acids to the ribosome during translation?

Accepted Answer

tRNA

Question 8

Given the DNA template strand 3'-ATGAAGCCGAGTCAT-5', what is the correct mRNA transcript?

Accepted Answer

3'-UACUUCGGCUCAGUA-5'

Question 9

A particular triplet of bases in the template strand of DNA is 5′-AGT-3′. What would be the corresponding codon for the mRNA that is transcribed?

Accepted Answer

3′-ACU-5′

Question 10

Which of the following best explains the redundancy of the genetic code?

Accepted Answer

There are more codons than amino acids

Question 11

What is the first event to take place in translation?

Accepted Answer

The small subunit of the ribosome recognizes and attaches to the mRNA

Question 12

Which of the following is a reversible form of post-translational modification that can activate or deactivate a protein?

Accepted Answer

Phosphorylation

Question 13

Which of the following statements about the lac operon is correct?

Accepted Answer

It is an inducible operon that is normally turned off

Question 14

How does extracellular glucose inhibit transcription of the lac operon?

Accepted Answer

By reducing the levels of intracellular cAMP

Question 15

Which of the following is true about operons in prokaryotes?

Accepted Answer

They allow the organism to simultaneously regulate transcription of multiple genes

Question 16

A mutation that inserts a single nucleotide just after the start codon in an mRNA is likely to:

Accepted Answer

Cause a frameshift mutation

Question 17

Which of the following is an example of positive regulation of gene expression?

Accepted Answer

A protein binds to DNA and then stimulates the initiation of transcription of a specific gene

Question 18

Which of the following modifications to chromatin structure is associated with increased transcription?

Accepted Answer

Histone acetylation

Question 19

Which of the following best describes the function of RNA interference (RNAi)?

Accepted Answer

Small RNA molecules interfere with translation by blocking a target mRNA’s ability to bind to a ribosome

Question 20

A hormone signal causes a cell to produce a large quantity of Protein X. After the signal disappears, how will the cell remove the excess Protein X?

Accepted Answer

The excess Protein X will be tagged with ubiquitin proteins and degraded over time

Gene Expression and Regulation: From DNA to Protein

Study Guide - Practice Questions