Question 1

Which of the following best describes the structural difference between DNA and RNA nucleotides?

Accepted Answer

DNA nucleotides have a deoxyribose sugar and thymine, while RNA nucleotides have a ribose sugar and uracil.

Question 2

Which equation correctly represents the complementary base pairing in DNA?

Accepted Answer

$$A = T$$ and $$G = C$$

Question 3

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

Accepted Answer

DNA polymerase

Question 4

Which of the following best explains the difference between the leading and lagging strands during DNA replication?

Accepted Answer

The leading strand is synthesized continuously, while the lagging strand is synthesized in short fragments called Okazaki fragments.

Question 5

Which process is most similar to the biological replication of DNA, but uses heat to separate strands and synthetic primers?

Accepted Answer

Polymerase Chain Reaction (PCR)

Question 6

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

Accepted Answer

$$DNA \rightarrow RNA \rightarrow Protein$$

Question 7

A mutation changes a codon from $$GAA to$$ $$GAG. $$What effect will this have on the protein produced?

Accepted Answer

It may have no effect because both codons code for glutamic acid (silent mutation).

Question 8

Which of the following best describes the role of ribosomes in translation?

Accepted Answer

Ribosomes catalyze the formation of peptide bonds between amino acids using mRNA and tRNA.

Question 9

Which event occurs during post-translational modification of proteins?

Accepted Answer

Phosphorylation of amino acid residues

Question 10

Which of the following best explains why all cells in an individual are genetically identical, yet have distinct functions?

Accepted Answer

Gene expression is regulated so that different sets of genes are active in different cell types.

Question 11

Which region of DNA is most likely to increase gene expression when bound by transcription factors?

Accepted Answer

Enhancer

Question 12

A lactose-tolerant human has a mutation in the enhancer region of the lactase gene. What is the most likely effect of this mutation?

Accepted Answer

Increased lactase production in adulthood

Question 13

Which of the following best describes the effect of methylation on gene expression?

Accepted Answer

Methylation generally silences gene expression.

Question 14

Which of the following is a correct definition of a gene?

Accepted Answer

A segment of DNA that codes for a specific protein or functional RNA.

Question 15

Which process involves the removal of introns from a primary mRNA transcript?

Accepted Answer

Splicing

Question 16

Which of the following best explains how the epigenome provides cellular memory?

Accepted Answer

By reversible chemical modifications such as methylation that affect gene expression patterns over time.

Question 17

Which of the following is the correct sequence of events in translation?

Accepted Answer

Initiation, elongation, termination

Question 18

A mutation in the coding region of a gene changes the codon $$UAC ($$tyrosine) to $$UAA ($$stop). What is the most likely consequence?

Accepted Answer

The protein will be truncated due to premature termination.

Question 19

Which of the following best describes the role of tRNA in translation?

Accepted Answer

tRNA carries amino acids to the ribosome and matches them to the mRNA codon via its anticodon.

Question 20

Which of the following is NOT a function of post-transcriptional control of gene expression?

Accepted Answer

Direct synthesis of proteins from DNA

Molecular Genetics and Gene Expression: Study Guide

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