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

During transcription in prokaryotes, which sequence signals the end of transcription?

Accepted Answer

Terminator

Question 3

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

Accepted Answer

There are 64 possible codons, but only 20 amino acids.

Question 4

In eukaryotic cells, what is the role of small nuclear ribonucleoproteins (snRNPs) during RNA processing?

Accepted Answer

They remove introns and splice exons together.

Question 5

Which of the following best describes an inducible operon?

Accepted Answer

It is turned off unless an inducer is present.

Question 6

What is the effect of allolactose on the lac operon in E. coli?

Accepted Answer

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

Question 7

Which of the following is an example of post-transcriptional regulation in bacteria?

Accepted Answer

A riboswitch changing mRNA structure to stop translation.

Question 8

A mutation that results in a premature stop codon is called a:

Accepted Answer

Nonsense mutation

Question 9

Which of the following best explains why the genetic code is described as 'degenerate'?

Accepted Answer

Some amino acids are coded by more than one codon.

Question 10

Which of the following mechanisms is responsible for the horizontal transfer of antibiotic resistance genes between bacteria?

Accepted Answer

Conjugation involving plasmids

Question 11

A frameshift mutation is most likely to result from:

Accepted Answer

An insertion or deletion of one or more nucleotide pairs

Question 12

Which of the following is a function of plasmids in bacteria?

Accepted Answer

They may carry genes for antibiotic resistance.

Question 13

Which of the following statements about the Ames test is correct?

Accepted Answer

It detects the presence of mutagens by measuring the rate of reverse mutations.

Question 14

Which of the following best describes the process of conjugation in bacteria?

Accepted Answer

Transfer of DNA from one bacterium to another via direct cell-to-cell contact

Question 15

What is the role of cAMP in the regulation of the lac operon?

Accepted Answer

It binds to CAP, which then activates transcription of the lac operon.

Question 16

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

Accepted Answer

Spread of antibiotic resistance among pathogenic bacteria

Question 17

A bacterial cell that has acquired a new nutritional requirement not present in the parent cell is called a(n):

Accepted Answer

Auxotroph

Question 18

Which of the following is a method of direct selection for identifying mutants?

Accepted Answer

Growth on a medium containing an antibiotic

Question 19

Which of the following statements about transposons is TRUE?

Accepted Answer

They can move from one DNA region to another and may inactivate genes.

Question 20

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

Accepted Answer

They provide genetic diversity for natural selection to act upon.

Microbial Genetics: Gene Expression, Regulation, and Mutation

Study Guide - Practice Questions