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 sequence

Question 3

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

Accepted Answer

It is degenerate, meaning multiple codons can code for the same amino acid.

Question 4

In the lac operon, what happens when lactose is present in the environment?

Accepted Answer

Allolactose binds to the repressor, inactivating it and allowing transcription of the operon.

Question 5

Which of the following is a key difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

In eukaryotes, transcription occurs in the nucleus and translation in the cytoplasm.

Question 6

A mutation that results in a stop codon being introduced into the coding sequence is called:

Accepted Answer

A nonsense mutation

Question 7

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

Accepted Answer

It brings specific amino acids to the ribosome and matches them to the mRNA codon via its anticodon.

Question 8

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

Accepted Answer

A riboswitch in mRNA changes structure upon binding a metabolite, affecting translation.

Question 9

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

Accepted Answer

They alter the reading frame, changing every amino acid downstream of the mutation.

Question 10

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

Accepted Answer

It binds to CAP, allowing CAP to bind the promoter and enhance transcription when glucose is low.

Question 11

Which of the following is a method of horizontal gene transfer in bacteria?

Accepted Answer

Conjugation

Question 12

A bacterial cell acquires antibiotic resistance by taking up naked DNA from its environment. This process is called:

Accepted Answer

Transformation

Question 13

Which of the following best describes the function of plasmids in bacteria?

Accepted Answer

They often carry genes that confer advantageous traits, such as antibiotic resistance.

Question 14

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

Accepted Answer

It is used to identify chemicals that can cause mutations.

Question 15

A missense mutation in a gene results in which of the following?

Accepted Answer

A single amino acid change in the protein product.

Question 16

Which of the following is a characteristic of repressible operons?

Accepted Answer

They are usually on but can be turned off by a corepressor.

Question 17

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

Accepted Answer

DNA is transferred from one bacterium to another by a bacteriophage.

Question 18

Which of the following is a function of transposons?

Accepted Answer

They can move from one location to another within the genome, sometimes carrying antibiotic resistance genes.

Question 19

Which of the following best explains why natural selection can act on bacterial populations?

Accepted Answer

Mutations and genetic recombination create diversity in genotypes, providing material for selection.

Question 20

A bacterial strain is found to be unable to grow on minimal medium unless tryptophan is added. This strain is best described as:

Accepted Answer

An auxotroph

Microbial Genetics: Protein Synthesis, Gene Regulation, and Genetic Variation

Study Guide - Practice Questions