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

Question 1

Which of the following best describes the difference between genotype and phenotype?

Accepted Answer

Genotype refers to the genetic makeup, while phenotype refers to the observable traits.

Question 2

Which of the following statements about plasmids is correct?

Accepted Answer

Plasmids are circular DNA molecules that often confer survival advantages, such as antibiotic resistance.

Question 3

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

Accepted Answer

Helicase

Question 4

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

Accepted Answer

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

Question 5

Which process describes the transfer of genetic material from one bacterial cell to another via a pilus?

Accepted Answer

Conjugation

Question 6

A mutation changes a DNA sequence from 5'-ATG GGA TCC-3' to 5'-ATG GAA TCC-3'. What type of mutation is this?

Accepted Answer

Substitution (point mutation)

Question 7

Which of the following is a function of histones in eukaryotic cells?

Accepted Answer

They organize and package DNA to prevent tangling.

Question 8

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

Accepted Answer

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

Question 9

Which of the following is true about inducible operons such as the lac operon in E. coli?

Accepted Answer

They are off by default and can be turned on in the presence of a specific substrate.

Question 10

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

Accepted Answer

Binary fission

Question 11

Which of the following best describes the role of small noncoding RNAs in post-transcriptional regulation?

Accepted Answer

They bind to mRNAs and either tag them for destruction or prevent their translation.

Question 12

A scientist exposes bacterial cells to ultraviolet (UV) light, which causes thymine dimers in DNA. What type of mutagen is UV light?

Accepted Answer

Physical mutagen

Question 13

Which of the following is a correct pairing of nitrogenous bases in DNA?

Accepted Answer

Guanine (G) pairs with Cytosine (C)

Question 14

Which of the following best explains why redundancy in the genetic code is beneficial?

Accepted Answer

It provides protection against mutations by allowing some changes in DNA to not affect the amino acid sequence.

Question 15

Which enzyme is responsible for replacing RNA primers with DNA during DNA replication?

Accepted Answer

DNA polymerase I

Question 16

A bacterial cell acquires a gene for antibiotic resistance from its environment without direct contact with another cell. What process is this?

Accepted Answer

Transformation

Question 17

Which of the following is a function of DNA methylation in epigenetic regulation?

Accepted Answer

It prevents transcription by silencing genes.

Question 18

Which of the following best describes the role of riboswitches in gene regulation?

Accepted Answer

They are mRNAs with sensor regions that bind small molecules to control protein synthesis.

Question 19

Which of the following is true about transposons?

Accepted Answer

They are segments of DNA that can change their position within the genome.

Question 20

Which of the following is a possible outcome when a bacteriophage infects a bacterial cell during transduction?

Accepted Answer

The phage DNA immediately directs production of new phage particles (lytic cycle).

Genetics and Molecular Biology: Microbial Genetics, DNA Structure, and Gene Expression

Study Guide - Practice Questions