Question 1

Which enzyme is responsible for unwinding and unzipping the DNA double helix during prokaryotic DNA replication?

Accepted Answer

DNA helicase

Question 2

During prokaryotic DNA replication, why is the origin of replication typically AT-rich?

Accepted Answer

AT base pairs require less energy to separate due to fewer hydrogen bonds

Question 3

Which of the following best describes the difference between the leading and lagging strands during DNA replication?

Accepted Answer

The leading strand is synthesized continuously in the 5' to 3' direction, while the lagging strand is synthesized discontinuously in short segments

Question 4

What is the function of DNA polymerase I during prokaryotic DNA replication?

Accepted Answer

It removes RNA primers and replaces them with DNA nucleotides

Question 5

In the central dogma of molecular biology, what is the correct sequence of information flow?

Accepted Answer

DNA $\rightarrow$ RNA $\rightarrow$ Protein

Question 6

During transcription in bacteria, what is the role of the sigma factor?

Accepted Answer

It recruits RNA polymerase to the promoter region

Question 7

Which of the following statements about the start codon in bacteria is correct?

Accepted Answer

The start codon is AUG and codes for formyl-methionine

Question 8

Why can prokaryotes conduct transcription and translation simultaneously, but eukaryotes cannot?

Accepted Answer

Prokaryotes lack a nucleus, allowing both processes to occur in the cytoplasm

Question 9

Which type of operon is the lac operon, and how is it regulated?

Accepted Answer

Inducible operon, turned on by substrate (lactose)

Question 10

A mutation that changes a codon for an amino acid into a stop codon is called:

Accepted Answer

Nonsense mutation

Question 11

Which of the following best describes a frameshift mutation?

Accepted Answer

An insertion or deletion that alters the reading frame of the mRNA

Question 12

What is the purpose of the Ames test in microbiology?

Accepted Answer

To determine if a chemical is mutagenic and potentially carcinogenic

Question 13

Which enzyme seals the gaps between Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

DNA ligase

Question 14

In bacterial gene regulation, what happens when the repressor of a repressible operon is activated by binding to the corepressor?

Accepted Answer

Transcription of the operon is blocked

Question 15

Which of the following is NOT a mechanism of horizontal gene transfer in bacteria?

Accepted Answer

Replication

Question 16

A bacterium that can take up free DNA from its environment is described as:

Accepted Answer

Competent

Question 17

Which of the following repair mechanisms uses photolyase to directly reverse UV-induced DNA damage?

Accepted Answer

Photoreactivation

Question 18

Which of the following statements about tRNA is correct?

Accepted Answer

tRNA acts as a translator of the mRNA code into protein

Question 19

Which equation correctly represents the semi-conservative model of DNA replication?

Accepted Answer

$	ext{Parent DNA} ightarrow 	ext{1 Parent Strand} + 	ext{1 New Strand}$

Question 20

Which process involves a bacteriophage transferring DNA from a donor to a recipient cell?

Accepted Answer

Transduction

Microbial Genetics: DNA Replication, Gene Expression, Regulation, Mutations, and Recombination

Study Guide - Practice Questions