Question 1

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

A scientist discovers a mutation in a bacterial gene that results in a single amino acid change in the encoded protein. What type of mutation is this?

Accepted Answer

Missense mutation

Question 3

Which of the following statements correctly compares bacterial and eukaryotic DNA structure?

Accepted Answer

Bacterial DNA is typically circular and lacks histones, while eukaryotic DNA is linear and associated with histones.

Question 4

During DNA replication, which enzyme is responsible for synthesizing short RNA primers?

Accepted Answer

Primase

Question 5

Which of the following best explains the degeneracy of the genetic code?

Accepted Answer

Multiple codons can code for the same amino acid.

Question 6

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

Accepted Answer

Nonsense mutation

Question 7

Which of the following is a function of the lac operon in E. coli?

Accepted Answer

It enables the bacterium to metabolize lactose when glucose is not available.

Question 8

Which of the following best describes the role of snRNPs in eukaryotic cells?

Accepted Answer

They are involved in the removal of introns from pre-mRNA.

Question 9

In the process of transcription, what is the function of the promoter region?

Accepted Answer

It is the binding site for RNA polymerase to initiate transcription.

Question 10

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 11

A bacterial cell is exposed to ionizing radiation. Which of the following best describes the effect of this exposure?

Accepted Answer

It can cause double-stranded breaks in DNA, leading to mutations.

Question 12

Which of the following is true regarding conjugation in bacteria?

Accepted Answer

It involves direct cell-to-cell contact and transfer of plasmid DNA.

Question 13

Which of the following best describes a frameshift mutation?

Accepted Answer

It results from the insertion or deletion of nucleotides that are not multiples of three, altering the reading frame.

Question 14

Which of the following is a key difference between an intron and an exon?

Accepted Answer

Introns are non-coding sequences removed from pre-mRNA, while exons are coding sequences that remain in mature mRNA.

Question 15

Which of the following best explains how the Ames test is used to identify mutagenic compounds?

Accepted Answer

It measures the rate of reversion mutations in bacteria exposed to a potential mutagen.

Question 16

Which of the following is a function of microRNAs in eukaryotic gene regulation?

Accepted Answer

They bind to mRNA and inhibit its translation or promote its degradation.

Question 17

A bacterial cell with a mutation in the operator region of the lac operon that prevents repressor binding will:

Accepted Answer

Continuously express the lac operon genes, even in the absence of lactose.

Question 18

Which of the following best describes the process of generalized transduction?

Accepted Answer

A bacteriophage accidentally packages host bacterial DNA and transfers it to another bacterium.

Question 19

Which of the following is the correct sequence of events during translation initiation in prokaryotes?

Accepted Answer

The small ribosomal subunit binds to the mRNA, the initiator tRNA binds to the start codon, and the large ribosomal subunit joins.

Question 20

Which of the following best describes the function of photolyase in DNA repair?

Accepted Answer

It uses visible light energy to break covalent bonds in thymine dimers.

Microbial Genetics and Gene Regulation: Study Guide

Study Guide - Practice Questions

Study Guide - Flashcards