Question 1

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

Accepted Answer

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

Question 2

Which enzyme is responsible for synthesizing the majority of the new DNA strand during DNA replication in prokaryotes?

Accepted Answer

DNA polymerase III

Question 3

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

Accepted Answer

Nonsense mutation

Question 4

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

Accepted Answer

Multiple codons can code for the same amino acid.

Question 5

During the process of transcription in eukaryotes, which of the following occurs after the RNA polymerase reaches the termination sequence?

Accepted Answer

The RNA polymerase falls off the DNA and the new RNA transcript is released.

Question 6

Which of the following is a function of the enzyme ligase during DNA replication?

Accepted Answer

Joining Okazaki fragments on the lagging strand

Question 7

A bacterial cell is exposed to UV light, causing thymine dimers to form. Which DNA repair mechanism is most likely to fix this damage?

Accepted Answer

Excision repair

Question 8

Which of the following best describes an inducible operon?

Accepted Answer

It is off by default and can be activated under certain conditions.

Question 9

Which of the following is NOT a type of horizontal gene transfer in bacteria?

Accepted Answer

Binary fission

Question 10

A frameshift mutation is most likely to result from which of the following genetic changes?

Accepted Answer

Insertion of two nucleotides

Question 11

Which of the following statements about plasmids is TRUE?

Accepted Answer

Plasmids are pieces of DNA that exist outside of chromosomal DNA and often confer advantages such as antibiotic resistance.

Question 12

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

Accepted Answer

tRNA brings the correct amino acid to the ribosome by matching its anticodon to the mRNA codon.

Question 13

Which of the following is a real-life example of a repressible operon?

Accepted Answer

The arginine (arg) operon

Question 14

Which of the following is a post-transcriptional regulatory mechanism in eukaryotes?

Accepted Answer

Alternative splicing of mRNA

Question 15

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

Accepted Answer

The lagging strand is synthesized discontinuously in short segments because DNA polymerase can only add nucleotides in the 5' to 3' direction.

Question 16

Which of the following is a function of reverse transcriptase?

Accepted Answer

Synthesizing cDNA from an RNA template

Question 17

Which of the following best describes the effect of DNA methylation on gene expression?

Accepted Answer

It prevents transcription, effectively silencing the gene.

Question 18

Which of the following is a characteristic of a silent mutation?

Accepted Answer

It does not change the amino acid sequence of the protein.

Question 19

Which of the following is a common result of generalized transduction in bacteria?

Accepted Answer

A bacteriophage packages a random fragment of host DNA and transfers it to another bacterium.

Question 20

Which of the following best describes the 'cut-and-paste' mechanism of DNA transposons?

Accepted Answer

The transposon is excised from its original location and inserted into a new location, leaving a gap at the original site.

Microbial Genetics: Structure, Function, and Regulation

Study Guide - Practice Questions