Question 1

Which of the following best describes the structure of a DNA molecule?

Accepted Answer

A double-stranded helix composed of deoxyribonucleotides with complementary base pairing

Question 2

During DNA replication, which enzyme is responsible for adding nucleotides to the growing DNA strand?

Accepted Answer

DNA polymerase

Question 3

Which of the following best explains the function of the TATA box in eukaryotic transcription?

Accepted Answer

It serves as a promoter region where transcription factors and RNA polymerase bind to initiate transcription

Question 4

A mutation changes the DNA sequence from $$\mathrm{TAC} to$$ $$\mathrm{TAT}. $$What type of mutation is this, and what is its likely effect on the protein?

Accepted Answer

A silent mutation; it may not change the amino acid sequence due to redundancy in the genetic code

Question 5

Which of the following statements about chromatin is correct?

Accepted Answer

Euchromatin is loosely packed and associated with active gene expression

Question 6

In the lac operon of E. coli, what is the role of the inducer molecule allolactose?

Accepted Answer

It binds to the repressor, causing it to release from the operator and allowing transcription

Question 7

Which process occurs in eukaryotic cells but not in prokaryotic cells during mRNA maturation?

Accepted Answer

Addition of a 5' cap and poly-A tail

Question 8

A scientist discovers a new virus that contains RNA as its genetic material and replicates only inside host cells. Which of the following statements is most accurate?

Accepted Answer

The virus uses host cell machinery to replicate its RNA genome

Question 9

Which of the following best describes the process of RNA splicing in eukaryotic cells?

Accepted Answer

Removal of introns and joining of exons to produce mature mRNA

Question 10

A prion is best described as:

Accepted Answer

A misfolded protein that can induce other proteins to misfold, leading to disease

Question 11

Which equation correctly represents the complementary base pairing in DNA?

Accepted Answer

$$\mathrm{A} = \mathrm{T}$$, $$\mathrm{C} = \mathrm{G}$$

Question 12

Which of the following is a direct result of a nonsense mutation in a gene?

Accepted Answer

Premature termination of translation, resulting in a truncated protein

Question 13

Which step in gene expression is regulated by the presence of transcription factors binding to the promoter region?

Accepted Answer

Transcription initiation

Question 14

In a multicellular organism, cell differentiation is primarily controlled by:

Accepted Answer

Differential gene expression regulated by transcription factors and epigenetic modifications

Question 15

Which of the following is true regarding the lytic and lysogenic cycles of bacteriophages?

Accepted Answer

The lytic cycle results in immediate destruction of the host cell, while the lysogenic cycle integrates viral DNA into the host genome

Question 16

Which of the following best describes the role of noncoding RNAs in gene regulation?

Accepted Answer

They can bind to mRNA and prevent its translation, affecting gene expression

Question 17

A nucleosome consists of:

Accepted Answer

DNA wrapped around a core of histone proteins

Question 18

Which of the following is a function of DNA ligase during DNA replication?

Accepted Answer

Joins Okazaki fragments on the lagging strand

Question 19

Which of the following is a plausible consequence of a mutation in the promoter region of a gene?

Accepted Answer

The gene may not be transcribed efficiently, leading to reduced protein production

Question 20

Which of the following best explains why viruses are considered nonliving?

Accepted Answer

They cannot carry out metabolism or reproduce independently outside a host cell

General Biology Exam Review: Molecular Basis of Inheritance, Gene Expression, Regulation, and Viruses

Study Guide - Practice Questions

Study Guide - Flashcards