Question 1

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

Accepted Answer

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

Question 2

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

Accepted Answer

Helicase

Question 3

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

Accepted Answer

Nonsense mutation

Question 4

Which of the following statements about bacterial chromosomes is TRUE?

Accepted Answer

They are circular and supercoiled within the cell.

Question 5

What is the role of Okazaki fragments in DNA replication?

Accepted Answer

They are short DNA fragments synthesized on the lagging strand.

Question 6

Which of the following best explains why frameshift mutations are often more severe than base substitutions?

Accepted Answer

Frameshift mutations change the reading frame, altering every amino acid downstream.

Question 7

In the process of transcription in prokaryotes, what is the function of the promoter sequence?

Accepted Answer

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

Question 8

Which of the following is a correct pairing of DNA and RNA bases during transcription?

Accepted Answer

Thymine (T) in DNA pairs with Uracil (U) in RNA.

Question 9

Which of the following best describes the difference between vertical and horizontal gene transfer?

Accepted Answer

Vertical gene transfer occurs from parent to offspring; horizontal gene transfer occurs between cells of the same generation.

Question 10

A bacterial cell is exposed to a mutagen that causes the insertion of two extra nucleotides into a gene. What is the most likely outcome?

Accepted Answer

A frameshift mutation that alters the reading frame.

Question 11

Which of the following is TRUE about the genetic code?

Accepted Answer

There are 64 possible codons and 20 amino acids.

Question 12

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

Accepted Answer

DNA ligase

Question 13

In a repressible operon, what happens when a corepressor is present?

Accepted Answer

The repressor becomes active and gene expression is inhibited.

Question 14

Which of the following is a function of tRNA during translation?

Accepted Answer

It transports amino acids to the ribosome and matches them to the mRNA codon.

Question 15

A patient is infected with a bacterial strain that has acquired antibiotic resistance through horizontal gene transfer. Which process most likely contributed to this resistance?

Accepted Answer

Transfer of resistance genes from another bacterium

Question 16

Which of the following statements about RNA is FALSE?

Accepted Answer

RNA contains thymine instead of uracil.

Question 17

Which of the following best explains why DNA replication is described as 'semiconservative'?

Accepted Answer

Each new DNA molecule contains one original strand and one new strand.

Question 18

Which of the following is a consequence of a missense mutation?

Accepted Answer

A single amino acid in the protein is changed.

Question 19

In eukaryotic cells, what is the role of snRNPs during gene expression?

Accepted Answer

They remove introns and splice exons together in pre-mRNA.

Question 20

Which of the following best describes the energy source for DNA replication?

Accepted Answer

Hydrolysis of two phosphate groups from nucleoside triphosphates

Chapter 8 - Microbial Genetics: Structure, Function, and Mutation

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