Question 1

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

Accepted Answer

Genetic information flows from DNA to RNA to protein through replication, transcription, and translation.

Question 2

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

Accepted Answer

It defines the start site for RNA synthesis by RNA polymerase.

Question 3

During prokaryotic transcription, which factor helps RNA polymerase recognize the promoter?

Accepted Answer

Sigma factor

Question 4

In which direction does RNA polymerase synthesize RNA?

Accepted Answer

5' to 3' direction using the template strand

Question 5

What determines the reading frame for translation on an mRNA molecule?

Accepted Answer

The first AUG start codon encountered by the ribosome

Question 6

What is the consequence of a point mutation in the start codon of a gene?

Accepted Answer

Translation may start at the next available AUG codon, resulting in a truncated protein.

Question 7

Which of the following is true about silent mutations?

Accepted Answer

They do not alter the amino acid sequence due to the redundancy of the genetic code.

Question 8

Which amino acids will never have a silent mutation in their codons?

Accepted Answer

Methionine and Tryptophan

Question 9

What happens when a point mutation occurs in the stop codon of a gene?

Accepted Answer

Translation continues until another stop codon is encountered, potentially producing a longer protein.

Question 10

Which process is responsible for marking proteins for degradation in the cell?

Accepted Answer

Ubiquitination

Question 11

What is the function of the proteasome in protein regulation?

Accepted Answer

It hydrolyzes and degrades ubiquitinated proteins.

Question 12

Which of the following is a consequence of a missense mutation in a gene?

Accepted Answer

A different amino acid is incorporated, which may affect protein folding and function.

Question 13

What is the role of the Met-initiator tRNA during translation?

Accepted Answer

It initiates translation by binding to the start codon (AUG).

Question 14

Which enzyme is responsible for hydrolyzing polysaccharides in bacterial cell walls?

Accepted Answer

Lysozyme

Question 15

What is the effect of mutating Glu35 to Ala35 in lysozyme?

Accepted Answer

Lysozyme activity is blocked or greatly reduced.

Question 16

Which of the following statements about GTP-binding proteins (GTPases) is correct?

Accepted Answer

They act as molecular switches, being active when bound to GTP and inactive when bound to GDP.

Question 17

A mutation in K-Ras GTPase that prevents GTP hydrolysis will most likely result in:

Accepted Answer

K-Ras being permanently active, leading to uncontrolled cell growth.

Question 18

Which of the following best explains why some codon changes are silent mutations?

Accepted Answer

Because the genetic code is degenerate, multiple codons can code for the same amino acid.

Question 19

Which step in translation is catalyzed by the large ribosomal subunit?

Accepted Answer

Formation of the first peptide bond between amino acids

Question 20

Which of the following is a real-world consequence of a mutation that creates a premature stop codon in a gene?

Accepted Answer

The protein will be truncated and may lose its function.

The Central Dogma of Molecular Biology and Genetic Mutations

Study Guide - Practice Questions