Question 1

Which of the following best describes the difference between the genomes of prokaryotic and eukaryotic cells?

Accepted Answer

Eukaryotic genomes are composed of multiple linear chromosomes located in the nucleus, while prokaryotic genomes are typically a single circular chromosome found in the cytoplasm.

Question 2

During DNA replication, why is the lagging strand synthesized in short fragments known as Okazaki fragments?

Accepted Answer

Because DNA polymerase works in only one direction, synthesizing new DNA in the 5' to 3' direction.

Question 3

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Question 4

A mutation that results in the substitution of one amino acid for another in a protein is called:

Accepted Answer

Missense mutation

Question 5

Which of the following best explains why the origin of replication in bacterial chromosomes is AT-rich?

Accepted Answer

AT base pairs are easier to separate because they form only two hydrogen bonds.

Question 6

Which of the following processes involves the transfer of genetic material from one bacterial cell to another via a pilus and requires direct cell-to-cell contact?

Accepted Answer

Conjugation

Question 7

A frameshift mutation can be caused by which of the following genetic events?

Accepted Answer

A deletion of one nucleotide

Question 8

In the lac operon, what is the role of lactose when it is present in the environment?

Accepted Answer

It binds to the repressor, inactivating it and allowing transcription of the operon.

Question 9

Which of the following statements about transcription in prokaryotes is correct?

Accepted Answer

Transcription and translation can occur simultaneously in the cytoplasm.

Question 10

A scientist exposes a bacterial culture to a chemical mutagen and observes that the bacteria can now grow on minimal medium, which they could not do before. What type of mutation has most likely occurred?

Accepted Answer

Back-mutation

Question 11

Which of the following best describes the function of tRNA during translation?

Accepted Answer

It acts as a translator by matching its anticodon to mRNA codons and bringing the correct amino acid.

Question 12

Which of the following is a real-world application of the Ames test?

Accepted Answer

Testing chemicals for their potential to cause mutations in DNA

Question 13

A mutation changes the codon UAU (tyrosine) to UAA (stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 14

Which of the following best explains why frameshift mutations are often more severe than point mutations?

Accepted Answer

They change the reading frame, potentially altering every amino acid downstream of the mutation.

Question 15

Which of the following is NOT a function of DNA polymerase during DNA replication?

Accepted Answer

Unwinding the DNA double helix

Question 16

A bacterial cell acquires a gene for antibiotic resistance from a lysed cell in its environment. This process is best described as:

Accepted Answer

Transformation

Question 17

Which of the following statements about the genetic code is correct?

Accepted Answer

The genetic code is universal and redundant.

Question 18

In eukaryotic cells, what is the fate of introns during gene expression?

Accepted Answer

They are spliced out of the pre-mRNA before translation.

Question 19

Which of the following best describes a repressible operon?

Accepted Answer

It is normally on and is turned off when the product of the pathway is abundant.

Question 20

A bacteriophage accidentally packages a random fragment of host DNA and transfers it to another bacterium. This process is called:

Accepted Answer

Generalized transduction

Chapter 9: Microbial Genetics: Structure, Function, and Regulation of Genetic Material

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