Question 1

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

Accepted Answer

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

Question 2

Which of the following statements about the sugar-phosphate backbone of DNA is correct?

Accepted Answer

It is formed by phosphodiester bonds between the 3' hydroxyl of one nucleotide and the 5' phosphate of the next.

Question 3

Which of the following is a purine found in DNA?

Accepted Answer

Adenine

Question 4

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

Accepted Answer

DNA helicase

Question 5

In the central dogma of molecular biology, which process directly produces mRNA from DNA?

Accepted Answer

Transcription

Question 6

Which of the following codons serves as the universal start codon in translation?

Accepted Answer

$$\mathrm{AUG}$$

Question 7

A mutation changes a DNA codon from $$\mathrm{TAC} to$$ $$\mathrm{TAA}. $$What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 8

Which of the following best explains why ETEC (Enterotoxigenic E. coli) can cause disease while most E. coli strains do not?

Accepted Answer

ETEC acquired plasmid-encoded genes for toxins through horizontal gene transfer.

Question 9

Which of the following mechanisms of horizontal gene transfer involves a bacteriophage?

Accepted Answer

Transduction

Question 10

Which of the following statements about prokaryotic gene expression is correct?

Accepted Answer

Transcription and translation occur simultaneously in the cytoplasm.

Question 11

A patient is diagnosed with necrotizing fasciitis caused by Streptococcus pyogenes. Which virulence factor is most directly responsible for the rapid spread of infection through connective tissue?

Accepted Answer

Hyaluronidase

Question 12

Which of the following best describes the difference between the leading and lagging strands during DNA replication?

Accepted Answer

The leading strand is synthesized continuously, while the lagging strand is synthesized in short fragments.

Question 13

Which of the following is true regarding the structure of RNA compared to DNA?

Accepted Answer

RNA contains uracil instead of thymine.

Question 14

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

Accepted Answer

Insertion or deletion of one or more bases

Question 15

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 16

Which of the following is the correct sequence of events in the central dogma of molecular biology?

Accepted Answer

DNA replication → transcription → translation

Question 17

Which of the following best describes the function of the promoter region in a gene?

Accepted Answer

It is the site where RNA polymerase binds to initiate transcription.

Question 18

Which of the following is a likely consequence of a missense mutation in a gene?

Accepted Answer

Substitution of one amino acid for another in the protein sequence.

Question 19

Which of the following best explains why antibiotic therapy is not usually recommended for EHEC (enterohemorrhagic E. coli) infections?

Accepted Answer

Antibiotics can increase the risk of endotoxic shock by causing massive release of Shiga toxin.

Question 20

Which of the following best describes the role of the 'wobble position' in the genetic code?

Accepted Answer

It allows for some variation in the third base of a codon without changing the amino acid specified.

Biochemistry of the Genome & Mechanisms of Microbial Genetics: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards