Question 1

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

Accepted Answer

Eukaryotic genomes are composed of multiple linear chromosomes, while prokaryotic genomes are typically a single circular chromosome.

Question 2

A gene is defined as:

Accepted Answer

A segment of DNA that contains the necessary code to make a protein or RNA molecule.

Question 3

Which of the following is NOT a component of a DNA nucleotide?

Accepted Answer

Uracil

Question 4

During DNA replication, which enzyme is responsible for unwinding and unzipping the DNA double helix?

Accepted Answer

Helicase

Question 5

In the process of DNA replication, what is meant by 'semiconservative' replication?

Accepted Answer

Each new DNA molecule consists of one old (parental) strand and one new strand.

Question 6

Which of the following base pairs is stabilized by three hydrogen bonds in DNA?

Accepted Answer

Guanine-Cytosine

Question 7

If the template DNA strand has the sequence $5'-TACGGT-3'$, what will be the sequence of the mRNA transcribed from this region?

Accepted Answer

$5'-AUGCCA-3'$

Question 8

Which statement correctly describes the function of tRNA during translation?

Accepted Answer

tRNA carries amino acids to the ribosome and matches its anticodon to the mRNA codon.

Question 9

In prokaryotes, how are transcription and translation related?

Accepted Answer

Transcription and translation are coupled; translation can begin while mRNA is still being synthesized.

Question 10

Which of the following best describes an inducible operon?

Accepted Answer

It is turned ON in the presence of the substrate and codes for catabolic enzymes.

Question 11

What is the role of the repressor protein in the lac operon when lactose is absent?

Accepted Answer

It binds to the operator and blocks transcription.

Question 12

Which of the following is true about repressible operons such as the trp operon?

Accepted Answer

They are turned OFF by the accumulation of the product (e.g., tryptophan).

Question 13

A mutation that changes a single nucleotide in a gene, resulting in a nonfunctional protein, is most likely to be:

Accepted Answer

Harmful and possibly fatal to the organism.

Question 14

Which process involves the transfer of genetic material from a donor to a recipient cell via a pilus?

Accepted Answer

Conjugation

Question 15

A bacterium acquires resistance to an antibiotic through the uptake of a plasmid from its environment. This is an example of:

Accepted Answer

Transformation

Question 16

Which of the following best explains why mutations are important in evolution?

Accepted Answer

Mutations introduce genetic variation, which can be selected for or against by environmental pressures.

Question 17

During transduction, what is the role of a bacteriophage?

Accepted Answer

It serves as a carrier of host DNA fragments to a new bacterial cell.

Question 18

Which enzyme is responsible for joining Okazaki fragments during DNA replication?

Accepted Answer

DNA ligase

Question 19

A mutation in the gene coding for hemoglobin changes the codon $GAG$ (glutamic acid) to $GTG$ (valine). What type of mutation is this?

Accepted Answer

Missense mutation

Question 20

Which of the following is a function of DNA polymerase during DNA replication?

Accepted Answer

Proofreading and correcting errors in newly synthesized DNA strands.

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

Study Guide - Practice Questions