Question 1

Which of the following best describes the process of vertical gene transfer in bacteria?

Accepted Answer

The transmission of genetic information from parent to offspring during cell division.

Question 2

A mutation changes a codon from UAU (tyrosine) to UAA. What type of mutation has occurred, and what is its likely effect on the protein?

Accepted Answer

Nonsense mutation; translation will terminate prematurely.

Question 3

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

Accepted Answer

DNA ligase

Question 4

Which of the following statements about the central dogma of molecular biology is correct?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 5

A bacterial cell is exposed to nitrous acid, which causes adenine to pair with cytosine instead of thymine. What type of mutation is most likely to result?

Accepted Answer

Base substitution mutation

Question 6

Which of the following best explains why bacterial translation can begin before transcription is complete?

Accepted Answer

Bacteria lack a nuclear membrane, so ribosomes can access mRNA as it is synthesized.

Question 7

A researcher discovers a bacterial strain that cannot grow on minimal media unless tryptophan is added. What is the best term for this mutant?

Accepted Answer

Auxotroph

Question 8

Which of the following is a key feature of the lagging strand during DNA replication?

Accepted Answer

It is synthesized discontinuously as Okazaki fragments.

Question 9

In the lac operon, what happens when lactose is present in the environment?

Accepted Answer

An inducer binds to the repressor, allowing transcription of the operon.

Question 10

Which of the following best describes the function of snRNPs in eukaryotic cells?

Accepted Answer

They remove introns and splice exons together during RNA processing.

Question 11

A bacterial cell is exposed to UV radiation, resulting in the formation of thymine dimers. Which DNA repair mechanism is most likely to correct this damage?

Accepted Answer

Photolyase-mediated repair

Question 12

Which of the following statements about plasmids is correct?

Accepted Answer

Plasmids are self-replicating, extrachromosomal circular DNA molecules.

Question 13

A bacterium acquires a new gene by taking up naked DNA from its environment. This process is known as:

Accepted Answer

Transformation

Question 14

Which of the following best explains the concept of catabolite repression in bacterial gene regulation?

Accepted Answer

The presence of glucose inhibits the expression of genes involved in the metabolism of other sugars.

Question 15

A scientist is mapping bacterial genes using Hfr conjugation. If gene A is transferred at 5 minutes and gene B at 15 minutes, what does this indicate?

Accepted Answer

Gene A is located closer to the origin of transfer than gene B.

Question 16

Which of the following is a direct result of a frameshift mutation?

Accepted Answer

The reading frame of the gene is altered, potentially changing every amino acid downstream.

Question 17

Which of the following best describes the role of transposase in bacterial cells?

Accepted Answer

It facilitates the movement of transposons within the genome.

Question 18

In the context of the Ames test, what does a high rate of reversion to prototrophy indicate?

Accepted Answer

The tested substance is likely mutagenic.

Question 19

Which of the following statements about genetic recombination in bacteria is correct?

Accepted Answer

It results in the exchange of genes between two DNA molecules, increasing genetic diversity.

Question 20

Which of the following best explains why natural selection is important in microbial evolution?

Accepted Answer

It ensures that only the most advantageous traits are passed to future generations.

Microbial Genetics: Structure, Function, and Variation

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