Q: Which of the following equations correctly expresses the mutation rate if 1 in every 1,000,000 genes mutates per cell division?

$$\text{Mutation rate} = 10$$^{-6}$$

Question 1

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

Accepted Answer

It synthesizes a new DNA strand by adding nucleotides to a pre-existing chain, using the parental strand as a template.

Question 2

During transcription in prokaryotes, which of the following statements is TRUE?

Accepted Answer

The mRNA produced can be immediately translated by ribosomes in the cytoplasm.

Question 3

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

Accepted Answer

Nonsense mutation

Question 4

Which of the following best explains why the lagging strand of DNA is synthesized discontinuously?

Accepted Answer

DNA polymerase can only add nucleotides in the 5' to 3' direction, so the lagging strand is synthesized in short fragments called Okazaki fragments.

Question 5

Which of the following is a function of plasmids in bacteria?

Accepted Answer

They may carry genes for antibiotic resistance, toxin production, or catabolism of unusual substances.

Question 6

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

Accepted Answer

It acts as an inducer, binding to the repressor and inactivating it, allowing transcription.

Question 7

Which of the following best describes a frameshift mutation?

Accepted Answer

One or more nucleotide pairs are inserted or deleted, altering the reading frame of the gene.

Question 8

Which process allows bacteria to acquire new genetic traits from dead cells in their environment?

Accepted Answer

Transformation

Question 9

A bacterial cell is exposed to UV light, resulting in the formation of thymine dimers. Which enzyme can directly repair this damage using visible light?

Accepted Answer

Photolyase

Question 10

Which of the following equations correctly expresses the mutation rate if 1 in every 1,000,000 genes mutates per cell division?

Accepted Answer

$$	ext{Mutation rate} = 10$$^{-6}$$

Question 11

Which of the following is an example of positive (direct) selection for mutants?

Accepted Answer

Plating bacteria on a medium containing penicillin to isolate penicillin-resistant colonies.

Question 12

Which of the following statements about horizontal gene transfer is correct?

Accepted Answer

It involves the transfer of genetic material between organisms of the same generation.

Question 13

Which of the following best describes the role of cAMP in the regulation of the lac operon?

Accepted Answer

cAMP binds to the catabolite activator protein (CAP), allowing CAP to bind to the promoter and enhance transcription when glucose is scarce.

Question 14

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

Accepted Answer

In eukaryotes, transcription and translation are separated by the nuclear membrane.

Question 15

A bacterial cell is found to have acquired resistance to an antibiotic after exposure to a plasmid from another cell. This is an example of:

Accepted Answer

Horizontal gene transfer via conjugation

Question 16

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

Accepted Answer

Transfer of DNA from one bacterium to another via a bacteriophage.

Question 17

Which of the following is a likely consequence of a frameshift mutation in a gene encoding an essential enzyme?

Accepted Answer

The enzyme will be truncated and likely nonfunctional due to a shift in the reading frame.

Question 18

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

Accepted Answer

It can bring together new combinations of genes that may be beneficial for survival.

Question 19

Which of the following best describes the function of transposons?

Accepted Answer

They are segments of DNA that can move from one region of a DNA molecule to another, sometimes carrying antibiotic resistance genes.

Question 20

A scientist is studying a bacterial strain that cannot synthesize the amino acid histidine and must be supplied with it in the growth medium. This strain is best described as:

Accepted Answer

An auxotroph

Microbial Genetics: Structure, Function, and Transfer of Genetic Information

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