Question 1

Which of the following best describes the difference between genotype and phenotype in a bacterial cell?

Accepted Answer

Genotype is the set of genes an organism carries, while phenotype is the expression of those genes.

Question 2

During DNA replication in bacteria, which enzyme is responsible for synthesizing short RNA primers needed to initiate DNA synthesis?

Accepted Answer

Primase

Question 3

Which of the following statements about the antiparallel structure of DNA is correct?

Accepted Answer

One DNA strand runs 5' to 3', and the other runs 3' to 5'.

Question 4

A mutation changes the DNA sequence from $$	ext{TAC} to$$ $$	ext{TAA}. $$What type of mutation is this, and what is its likely effect on the protein?

Accepted Answer

Nonsense mutation; introduces a stop codon

Question 5

Which process allows for the horizontal transfer of genetic material between bacteria using a virus as a vector?

Accepted Answer

Transduction

Question 6

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

Accepted Answer

Lactose binds to the repressor, preventing it from binding to the operator, allowing transcription.

Question 7

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

Accepted Answer

It joins Okazaki fragments on the lagging strand.

Question 8

A bacterial cell is exposed to UV light, resulting in the formation of thymine dimers. Which enzyme is directly responsible for repairing this damage?

Accepted Answer

Endonuclease

Question 9

Which of the following is a property of the genetic code?

Accepted Answer

The code is degenerate, meaning multiple codons can code for the same amino acid.

Question 10

Which of the following best explains why the trp operon is considered repressible?

Accepted Answer

It is turned off when tryptophan is abundant, preventing unnecessary synthesis.

Question 11

A scientist uses the Ames test to evaluate a chemical. If the chemical is a mutagen, what result should be expected?

Accepted Answer

More colonies of revertant bacteria on the experimental plate compared to the control.

Question 12

Which of the following is true about plasmids in bacteria?

Accepted Answer

They are self-replicating, circular DNA molecules that may carry antibiotic resistance genes.

Question 13

During translation, which site on the ribosome does the incoming aminoacyl-tRNA first bind?

Accepted Answer

A site

Question 14

Which of the following best describes a frameshift mutation?

Accepted Answer

A mutation caused by insertion or deletion of nucleotides, altering the reading frame.

Question 15

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

Accepted Answer

Spread of antibiotic resistance genes among pathogenic bacteria.

Question 16

Which of the following is required for the initiation of transcription in bacteria?

Accepted Answer

A promoter sequence

Question 17

A scientist observes that a bacterial cell can metabolize a new sugar after exposure to DNA from another species. Which process most likely occurred?

Accepted Answer

Transformation

Question 18

Which of the following best explains why Okazaki fragments are formed during DNA replication?

Accepted Answer

DNA polymerase can only add nucleotides to the 3' end, so the lagging strand is synthesized in short segments.

Question 19

Which of the following is a function of the RecA protein in genetic recombination?

Accepted Answer

It catalyzes the joining of homologous DNA strands during recombination.

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

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