Question 1

Which of the following best describes the primary difference between prokaryotic and eukaryotic genomes?

Accepted Answer

Prokaryotic genomes are small, mostly coding, circular, and lack histones, while eukaryotic genomes are large, mostly noncoding, linear, and packed with histones.

Question 2

DNA methylation most commonly leads to which of the following outcomes in gene regulation?

Accepted Answer

Repression of transcription by promoting chromatin condensation.

Question 3

Which of the following modifications is most likely associated with actively transcribed genes?

Accepted Answer

Histone acetylation and open chromatin structure.

Question 4

A mutation in a gene's enhancer region is most likely to affect gene expression by:

Accepted Answer

Changing the rate of transcription by affecting transcription factor binding.

Question 5

Which of the following is a cis-regulatory element?

Accepted Answer

Enhancer

Question 6

What is the main function of insulator sequences in gene regulation?

Accepted Answer

They block the interaction between enhancers and promoters when positioned between them.

Question 7

Which of the following best explains how alternative splicing can contribute to protein diversity in humans?

Accepted Answer

By allowing different exons to be included or excluded from the final mRNA, resulting in different protein isoforms.

Question 8

A researcher finds that a gene is highly expressed in liver cells but not in brain cells. Which regulatory mechanism is most likely responsible for this tissue-specific expression?

Accepted Answer

Presence of tissue-specific activator proteins binding to enhancers in liver cells.

Question 9

Which of the following is a direct effect of microRNA (miRNA) in post-transcriptional gene regulation?

Accepted Answer

miRNA binds to complementary mRNA sequences and promotes their degradation or inhibits translation.

Question 10

Which of the following best describes the role of the TATA box in eukaryotic gene transcription?

Accepted Answer

It is a consensus sequence in the promoter that helps position RNA polymerase II for transcription initiation.

Question 11

A scientist is studying a gene with a CpG island near its promoter. She finds that the CpG island is heavily methylated in muscle cells but unmethylated in skin cells. What is the most likely outcome?

Accepted Answer

The gene is repressed in muscle cells and actively transcribed in skin cells.

Question 12

Which of the following equations correctly represents the calculation of recombination frequency ($$RF) $$between two genes?

Accepted Answer

$$RF = \frac{	ext{Number of recombinant offspring}}{	ext{Total number of offspring}} 	imes 100\%$$

Question 13

Which of the following is a trans-regulatory element involved in gene expression?

Accepted Answer

Transcription factor

Question 14

What is the primary function of the RNA-induced silencing complex (RISC) in gene regulation?

Accepted Answer

It degrades or inhibits translation of target mRNAs guided by siRNA or miRNA.

Question 15

Which of the following post-translational modifications is responsible for targeting proteins for degradation in the proteasome?

Accepted Answer

Ubiquitination

Question 16

A gene is found to be transcribed at very low levels in brain cells but at high levels in liver cells. Which regulatory element is most likely bound in the brain cells to cause this difference?

Accepted Answer

Repressor protein bound to a silencer element

Question 17

Which of the following best describes the effect of histone acetylation on chromatin structure and gene expression?

Accepted Answer

It relaxes chromatin and promotes gene expression.

Question 18

Which of the following statements about the directionality of genetic information flow is correct?

Accepted Answer

DNA is read in the 3' to 5' direction during transcription, RNA is synthesized in the 5' to 3' direction, and proteins are translated from the N-terminus to the C-terminus.

Question 19

Which of the following best describes the function of chromatin remodeling complexes?

Accepted Answer

They reposition nucleosomes to make DNA accessible or inaccessible to transcription factors and RNA polymerase.

Transcriptional and Post-Transcriptional Regulation of Gene Expression

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