Question 1

Which of the following best describes the primary difference between genetic and epigenetic changes?

Accepted Answer

Epigenetic changes modify gene expression without altering the DNA sequence, whereas genetic changes involve alterations in the DNA sequence itself.

Question 2

A pregnant mouse is fed a diet rich in methyl donors, resulting in offspring with brown fur, while genetically identical mice whose mothers did not receive this diet have yellow fur. What is the most likely explanation for this difference?

Accepted Answer

Increased DNA methylation in the promoter region of the Agouti gene silenced its expression, leading to brown fur.

Question 3

Which of the following is a common mechanism by which epigenetic regulation occurs?

Accepted Answer

DNA methylation at cytosine residues, especially at CpG sites

Question 4

Which enzyme is responsible for adding acetyl groups to histone proteins, thereby generally increasing gene expression?

Accepted Answer

Histone acetyltransferase (HAT)

Question 5

A researcher observes that a gene is transcriptionally silent in a cell. Which of the following epigenetic modifications is most likely present at this gene's promoter?

Accepted Answer

High levels of DNA methylation at CpG islands

Question 6

Which of the following statements about epigenetic inheritance is most accurate?

Accepted Answer

Some epigenetic marks may be retained and passed to offspring, but the extent of transgenerational epigenetic inheritance in humans is still debated.

Question 7

Which of the following best explains why identical twins can have different disease susceptibilities despite having the same DNA sequence?

Accepted Answer

They accumulate different epigenetic modifications due to environmental and lifestyle factors.

Question 8

Which of the following is an example of a reversible epigenetic change in humans?

Accepted Answer

DNA methylation changes at the AHRR gene in smokers that can return to normal after quitting smoking

Question 9

In the context of epigenetics, what is the function of 'reader' proteins?

Accepted Answer

They recognize and bind to specific epigenetic marks, influencing downstream gene expression.

Question 10

A study finds that children of mothers with gestational diabetes have a higher risk of developing type 2 diabetes later in life. Which epigenetic mechanism is most likely involved in this increased risk?

Accepted Answer

Epigenetic modifications, such as altered DNA methylation, induced by high glucose exposure during fetal development

Question 11

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

Accepted Answer

Histone acetylation relaxes chromatin, promoting gene expression.

Question 12

Which of the following is NOT considered a classic epigenetic mechanism?

Accepted Answer

Single nucleotide polymorphism (SNP)

Question 13

A group of rats exposed to high maternal care show reduced methylation at the promoter of the glucocorticoid receptor (GR) gene. What is the likely outcome for these rats?

Accepted Answer

They will have increased expression of the GR gene and better stress response.

Question 14

Which of the following best explains why epigenetic changes can be cell-type specific, even though all cells in an organism have the same DNA sequence?

Accepted Answer

Epigenetic modifications regulate which genes are active or silenced in each cell type.

Question 15

Which of the following is a plausible real-world example of transgenerational epigenetic inheritance in mammals?

Accepted Answer

Epigenetic marks in sperm DNA associated with a learned fear response to a specific scent, observed in both offspring and grand-offspring

Question 16

Which of the following statements about DNA methylation is correct?

Accepted Answer

DNA methylation at CpG islands in gene promoters typically represses gene expression.

Question 17

A scientist is studying the effects of environmental enrichment on mice and finds increased levels of specific microRNAs in the sperm of enriched males. What is the most likely implication of this finding?

Accepted Answer

These microRNAs may mediate the transmission of enhanced cognitive traits to the next generation via epigenetic inheritance.

Question 18

Which of the following best describes the role of chromatin remodeling complexes in epigenetic regulation?

Accepted Answer

They rearrange nucleosomes to alter DNA accessibility for transcription factors.

Question 19

Which of the following lifestyle factors has NOT been shown to influence epigenetic patterns in humans?

Accepted Answer

Blood type

Epigenetics: Mechanisms and Examples in Human Genetics

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