Question 1

Which of the following best describes the function of plasmids in prokaryotic cells?

Accepted Answer

They carry information required for their own replication and may confer survival advantages such as antibiotic resistance.

Question 2

During DNA replication in prokaryotes, which direction is the new DNA strand synthesized?

Accepted Answer

From 5' to 3'

Question 3

A mutation that results in the substitution of one base pair, changing a codon from coding for leucine to coding for proline, is best described as which type of mutation?

Accepted Answer

Missense mutation

Question 4

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

Accepted Answer

It is an inducible operon that is activated in the presence of lactose and absence of glucose.

Question 5

Which of the following best explains why DNA replication is described as 'semi-conservative'?

Accepted Answer

Each new DNA molecule consists of one original (parental) strand and one newly synthesized strand.

Question 6

A bacterium acquires antibiotic resistance by direct uptake of naked DNA from its environment. This process is called:

Accepted Answer

Transformation

Question 7

Which of the following is a correct pairing of nitrogenous bases in DNA?

Accepted Answer

Guanine–Cytosine

Question 8

In the trp operon, what happens when tryptophan is abundant in the environment?

Accepted Answer

Tryptophan acts as a corepressor, activating the repressor and turning the operon off.

Question 9

Which of the following best describes generalized transduction?

Accepted Answer

Transfer of random DNA segments from donor to recipient via a bacteriophage.

Question 10

A frameshift mutation can result from which of the following genetic events?

Accepted Answer

Insertion or deletion of one or more nucleotide pairs

Question 11

Which of the following is NOT a function of bacterial plasmids?

Accepted Answer

Carrying genes essential for normal cellular metabolism

Question 12

During translation in prokaryotes, which site on the ribosome first receives the tRNA carrying the next amino acid to be added to the polypeptide chain?

Accepted Answer

A site

Question 13

Which of the following best describes the difference between genotype and phenotype?

Accepted Answer

Genotype refers to the genes in the genome, while phenotype refers to the physical features and functional traits.

Question 14

Which of the following equations correctly represents the energy released during the addition of a nucleotide to a growing DNA strand?

Accepted Answer

$$dNTP \rightarrow dNMP + PP_i$$

Question 15

A bacterial cell that is able to transfer a plasmid to another cell via a pilus is said to possess which of the following?

Accepted Answer

A fertility factor

Question 16

Which of the following scenarios best illustrates horizontal gene transfer by conjugation?

Accepted Answer

A donor bacterium transfers a plasmid to a recipient bacterium through direct cell-to-cell contact.

Question 17

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

Accepted Answer

The enzyme will be truncated and likely nonfunctional due to an early stop codon.

Question 18

Which of the following best describes the role of the operator in a prokaryotic operon?

Accepted Answer

It is a regulatory element that controls the access of RNA polymerase to the genes.

Question 19

In the context of the central dogma of molecular biology, which sequence correctly represents the flow of genetic information?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 20

A patient is infected with a strain of Streptococcus pneumoniae that has acquired a capsule gene from a dead, encapsulated strain. Which genetic process most likely occurred?

Accepted Answer

Transformation

Microbial Genetics: Structure, Replication, and Expression of Genetic Material

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