Question 1

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

Accepted Answer

A phosphate group, a deoxyribose sugar, and a nitrogenous base

Question 2

During DNA replication, why is the lagging strand synthesized in Okazaki fragments?

Accepted Answer

Because DNA polymerase can only add nucleotides in the $$5' \rightarrow 3'$$ direction, and the lagging strand template runs $$3' \rightarrow 5'$$

Question 3

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

Accepted Answer

DNA ligase

Question 4

What is the function of telomeres in eukaryotic chromosomes?

Accepted Answer

They protect chromosome ends from deterioration and prevent fusion with neighboring chromosomes

Question 5

Which of the following best explains why the RNA primer at the $$5'$$ end of the leading strand cannot be replaced with DNA nucleotides?

Accepted Answer

DNA polymerase requires a free $$3'-OH $$group to add nucleotides, which is absent at the $$5'$$ end

Question 6

Which of the following statements about chromatin is correct?

Accepted Answer

Euchromatin is less condensed and transcriptionally active, while heterochromatin is highly condensed and transcriptionally inactive

Question 7

Which process describes the synthesis of a complementary RNA strand from a DNA template?

Accepted Answer

Transcription

Question 8

A mutation changes a DNA codon from $$AAA ($$lysine) to $$UAA ($$stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 9

Which of the following best describes the relationship between DNA, mRNA, tRNA, and protein synthesis?

Accepted Answer

DNA is transcribed into mRNA, which is translated by tRNA into a sequence of amino acids forming a protein

Question 10

Which of the following is a function of the 5' cap and poly(A) tail added to mRNA during processing?

Accepted Answer

They protect mRNA from degradation and assist in its export from the nucleus

Question 11

Which of the following best describes the role of spliceosomes?

Accepted Answer

They remove introns and join exons in the primary RNA transcript

Question 12

Which of the following is true regarding the genetic code?

Accepted Answer

Each mRNA codon corresponds to a specific tRNA anticodon and an amino acid

Question 13

Which of the following best explains the difference between repressible and inducible operons?

Accepted Answer

Repressible operons are usually active and can be turned off, while inducible operons are usually inactive and can be turned on

Question 14

Which of the following best describes epigenetic inheritance?

Accepted Answer

Inheritance of traits not directly involving changes in the DNA sequence, such as DNA methylation or histone modification

Question 15

Which of the following is a consequence of histone acetylation?

Accepted Answer

Chromatin becomes less condensed, increasing transcriptional activity

Question 16

A patient has a mutation that results in the insertion of a single nucleotide in a gene. What is the most likely effect on the protein?

Accepted Answer

A frameshift mutation, which alters the reading frame and can drastically change the protein's function

Question 17

Which of the following best describes the function of microRNAs (miRNAs)?

Accepted Answer

They bind to mRNA and inhibit its translation or promote its degradation

Question 18

Which of the following is the primary function of a proteasome?

Accepted Answer

To degrade and recycle proteins that are damaged or no longer needed

Question 19

Which of the following best describes the role of general transcription factors?

Accepted Answer

They are required for the transcription of all genes and help RNA polymerase bind to the promoter

Question 20

A scientist is studying a gene that can be alternatively spliced to produce two different proteins. Which process is responsible for this phenomenon?

Accepted Answer

Alternative RNA splicing

Comprehensive Guidance for DNA Structure, Replication, Gene Expression, and Regulation

Study Guide - Practice Questions