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

$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$$

Question 1

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

Accepted Answer

DNA ligase

Question 2

A mutation changes a codon from $$	ext{UAC} ($$tyrosine) to $$	ext{UAA} ($$stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 3

During the process of conjugation, which structure is primarily responsible for the transfer of genetic material between bacterial cells?

Accepted Answer

Pilus

Question 4

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

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 5

A bacterial cell is exposed to a mutagen that causes the insertion of a single nucleotide into a gene. What is the most likely result?

Accepted Answer

Frameshift mutation

Question 6

Which enzyme relieves supercoiling ahead of the replication fork during DNA replication?

Accepted Answer

Topoisomerase

Question 7

In the lac operon of E. coli, what happens when lactose is present and glucose is absent?

Accepted Answer

The operon is induced and transcription of lac genes increases.

Question 8

Which of the following is an example of horizontal gene transfer that involves a bacteriophage?

Accepted Answer

Transduction

Question 9

A patient is infected with a bacterial strain that has acquired antibiotic resistance via a plasmid. Which mechanism most likely explains this acquisition?

Accepted Answer

Horizontal gene transfer

Question 10

During translation, which molecule brings amino acids to the ribosome and matches them to the mRNA codon?

Accepted Answer

tRNA

Question 11

Which of the following best describes a silent mutation?

Accepted Answer

A mutation that does not change the amino acid sequence

Question 12

Which of the following is the correct sequence of events in gene expression according to the central dogma?

Accepted Answer

Transcription $$\rightarrow$$ Translation

Question 13

A riboswitch is best described as:

Accepted Answer

A regulatory RNA that controls gene expression by binding small molecules

Question 14

Which of the following enzymes is responsible for synthesizing RNA from a DNA template during transcription?

Accepted Answer

RNA polymerase

Question 15

A bacterial cell is able to take up naked DNA from its environment and incorporate it into its genome. This process is called:

Accepted Answer

Transformation

Question 16

Which of the following codon-anticodon pairings is correct for the mRNA codon $$	ext{AUG}$$?

Accepted Answer

Anticodon $$	ext{UAC}$$

Question 17

Which of the following statements about plasmids is TRUE?

Accepted Answer

Plasmids can carry antibiotic resistance genes.

Question 18

A mutation in the gene encoding DNA polymerase results in an enzyme that cannot proofread. What is the most likely consequence?

Accepted Answer

Increased mutation rate during DNA replication

Question 19

Which of the following best explains why the lagging strand is synthesized discontinuously?

Accepted Answer

DNA polymerase can only add nucleotides in the 5' to 3' direction.

Question 20

A researcher introduces a point mutation that changes the codon $$	ext{GAA} ($$glutamic acid) to $$	ext{GAG} ($$also glutamic acid). What type of mutation is this?

Accepted Answer

Silent mutation

Microbial Genetics and Gene Expression: Key Concepts and Mechanisms

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