Question 1

Which of the following best describes the function of DNA polymerase during DNA replication?

Accepted Answer

It adds nucleotides to the growing DNA strand in the 5' to 3' direction.

Question 2

A mutation changes a codon from UAU (tyrosine) to UAA. What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 3

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

Accepted Answer

It is induced when lactose is present and glucose is absent.

Question 4

Which enzyme is responsible for removing RNA primers and replacing them with DNA nucleotides during DNA replication?

Accepted Answer

DNA polymerase

Question 5

A bacterial cell is exposed to ionizing radiation. What is the most likely effect on its DNA?

Accepted Answer

Breaks in the DNA chromosome

Question 6

Which of the following best describes a transposon?

Accepted Answer

A segment of DNA that can move from one location to another within the genome

Question 7

During transcription in bacteria, what is the role of the promoter sequence?

Accepted Answer

It is the site where RNA polymerase binds to initiate transcription.

Question 8

Which of the following is a real-life example of horizontal gene transfer in bacteria?

Accepted Answer

A bacterium acquiring antibiotic resistance through conjugation with another bacterium

Question 9

Which of the following best explains why the genetic code is described as 'degenerate'?

Accepted Answer

Multiple codons can code for the same amino acid.

Question 10

A scientist exposes bacteria to nitrous acid, which converts adenine to hypoxanthine. What is the most likely genetic consequence?

Accepted Answer

Base-pair substitution mutation

Question 11

Which of the following is true about Okazaki fragments?

Accepted Answer

They are joined together by DNA ligase.

Question 12

In Griffith’s experiment, what was the outcome when living nonencapsulated bacteria and heat-killed encapsulated bacteria were injected into a mouse?

Accepted Answer

The mouse died, and living encapsulated bacteria were recovered.

Question 13

Which of the following best describes the difference between generalized and specialized transduction?

Accepted Answer

Generalized transduction can transfer any gene, while specialized transduction transfers only specific genes near the prophage site.

Question 14

Which of the following equations correctly represents the energy release when a nucleoside triphosphate is added to a growing DNA strand?

Accepted Answer

$$\mathrm{dNTP} ightarrow \mathrm{dNMP} + 2\mathrm{PP_i} + 	ext{energy}$$

Question 15

Which of the following is a function of the enzyme DNA ligase during DNA replication?

Accepted Answer

Joins Okazaki fragments together

Question 16

A mutation that results in the insertion or deletion of one or two nucleotides in a gene is most likely to cause which of the following?

Accepted Answer

Frameshift mutation

Question 17

Which of the following best describes the process of attenuation in the tryptophan operon?

Accepted Answer

It terminates transcription when tryptophan is abundant.

Question 18

Which of the following is a key difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

In prokaryotes, transcription and translation are coupled and can occur simultaneously.

Question 19

Which of the following best explains why bacteria growing in a medium containing both glucose and lactose first consume glucose before lactose?

Accepted Answer

Glucose inhibits the synthesis of cAMP, preventing activation of the lac operon.

Microbial Genetics: Structure, Function, and Regulation of Genetic Material

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