Question 1

Which of the following best explains why phenotypes can differ among genetically identical individuals, such as the Agouti mice, when exposed to different maternal diets?

Accepted Answer

Epigenetic modifications induced by environmental factors

Question 2

A methyl-rich maternal diet in Agouti mice leads to which of the following outcomes in offspring?

Accepted Answer

Silencing of the Agouti gene through DNA methylation, resulting in brown, lean mice

Question 3

Which of the following is a key reason why eukaryotic gene regulation is more complex than prokaryotic gene regulation?

Accepted Answer

Transcription and translation are physically separated in eukaryotes

Question 4

The TATA box is a core promoter element found in eukaryotic genes. At approximately what position relative to the transcription start site is the TATA box typically located?

Accepted Answer

$$-25$$

Question 5

Which of the following best describes the function of enhancer sequences in eukaryotic gene regulation?

Accepted Answer

They are cis-acting sequences that can increase transcription from a distance

Question 6

What is the primary role of insulator sequences in eukaryotic genomes?

Accepted Answer

To block or redirect enhancer activity, protecting genes from inappropriate regulation

Question 7

Which of the following histone modifications is generally associated with transcriptionally active euchromatin?

Accepted Answer

H3K9ac

Question 8

DNA methylation most commonly occurs at which nucleotide sequence in eukaryotes?

Accepted Answer

CpG dinucleotides

Question 9

Genomic imprinting results in parent-specific gene expression. Which gene is expressed from the paternal chromosome due to methylation of the insulator region?

Accepted Answer

IGF2

Question 10

Which experimental technique is primarily used to map topologically associating domains (TADs) in the genome?

Accepted Answer

Hi-C sequencing

Question 11

Which of the following best describes the mechanism of RNA interference (RNAi) in gene regulation?

Accepted Answer

Small non-coding RNAs bind to mRNA, leading to degradation or inhibition of translation

Question 12

Which protein complex is responsible for processing pre-miRNAs into mature miRNA duplexes in the cytoplasm?

Accepted Answer

Dicer

Question 13

A mutation that prevents acetylation of histone H3 at lysine 9 (H3K9ac) would most likely result in which of the following?

Accepted Answer

Decreased gene expression due to closed chromatin

Question 14

Which of the following is an example of a post-translational modification that can regulate protein function?

Accepted Answer

Cleavage of a polypeptide to activate the protein

Question 15

In the context of feedback inhibition in metabolic pathways, which equation best represents the effect of an end-product inhibitor on enzyme activity?

Accepted Answer

$$E + I \rightleftharpoons EI ($$where $$I is $$the inhibitor, reducing enzyme activity)

Question 16

Which of the following statements about cis-acting and trans-acting elements is correct?

Accepted Answer

Trans-acting elements are proteins that can regulate genes on different chromosomes

Question 17

A scientist wants to silence a gene in a human cell line to study its function. Which of the following approaches would be most effective?

Accepted Answer

Introduce a small interfering RNA (siRNA) complementary to the gene's mRNA

Question 18

Which of the following best describes the role of topologically associating domains (TADs) in gene regulation?

Accepted Answer

TADs are regions of DNA that interact preferentially with themselves, influencing which regulatory elements can contact specific genes

Question 19

Which of the following is a direct effect of DNA methylation at CpG islands near gene promoters?

Accepted Answer

Recruitment of methyl-CpG-binding proteins that promote chromatin condensation

Question 20

Which of the following scenarios best illustrates the concept of genomic imprinting?

Accepted Answer

Only the allele inherited from one parent is expressed due to epigenetic marks established during gamete formation

Gene Expression and Regulation in Eukaryotes

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