Question 1

Which of the following best describes the process of DNA replication in bacteria?

Accepted Answer

It is a semi-conservative process where each new DNA molecule consists of one old strand and one newly synthesized strand.

Question 2

During DNA replication, which enzyme is responsible for joining Okazaki fragments on the lagging strand?

Accepted Answer

DNA ligase

Question 3

A mutation that results in a premature stop codon is called:

Accepted Answer

Nonsense mutation

Question 4

Which of the following statements about the flow of genetic information in a bacterial cell is correct?

Accepted Answer

Both transcription and translation occur in the cytoplasm.

Question 5

In the lac operon, what is the role of allolactose?

Accepted Answer

It acts as an inducer by binding to the repressor and inactivating it.

Question 6

Which of the following best explains why UV light is mutagenic to DNA?

Accepted Answer

It causes the formation of thymine dimers, which distort the DNA structure.

Question 7

A bacterial cell is exposed to a chemical that increases the rate of mutation. This chemical is best described as a:

Accepted Answer

Mutagen

Question 8

Which of the following is an example of positive (direct) selection in microbiology?

Accepted Answer

Identifying bacteria that grow in the presence of an antibiotic.

Question 9

In the Ames test, what does the appearance of many colonies on a plate lacking histidine indicate?

Accepted Answer

The chemical tested has induced reverse mutations, restoring histidine independence.

Question 10

Which of the following best describes the function of the P53 gene in human cells?

Accepted Answer

It acts as a surveillance gene, helping to detect and repair DNA damage.

Question 11

A frameshift mutation is most likely to result from which of the following?

Accepted Answer

An insertion or deletion of one or more nucleotide pairs

Question 12

Which of the following is true regarding conjugation in bacteria?

Accepted Answer

It involves direct cell-to-cell contact and transfer of plasmid DNA via a sex pilus.

Question 13

A scientist discovers a bacterial strain that can metabolize a new compound due to a gene located on a plasmid. This plasmid is most likely a:

Accepted Answer

Dissimilation plasmid

Question 14

Which of the following best describes the process of transformation in bacteria?

Accepted Answer

Uptake of free DNA fragments from the environment by a competent cell

Question 15

In the context of gene regulation, which statement about repressible operons is correct?

Accepted Answer

Their default position is on, and they are turned off by a co-repressor.

Question 16

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

Accepted Answer

In eukaryotes, mRNA must be processed to remove introns before translation.

Question 17

A bacterial cell with an integrated F plasmid in its chromosome is called:

Accepted Answer

Hfr cell

Question 18

Which of the following best describes a transposon?

Accepted Answer

A segment of DNA that can move from one region of DNA to another

Question 19

Which of the following equations correctly represents the direction of DNA synthesis?

Accepted Answer

$$5' \rightarrow 3'$$

Question 20

A researcher is studying a bacterial population exposed to both glucose and lactose. According to the study materials, which sugar will the bacteria preferentially metabolize and why?

Accepted Answer

Glucose, because constitutive enzymes for glucose metabolism are always present.

Microbial Genetics: Structure, Function, and Mechanisms of Genetic Change

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