Question 1

Which of the following best explains why skin cells from an adult frog can give rise to a normal tadpole when their nucleus is transplanted into an enucleated egg, as shown in the image?

Accepted Answer

Skin cells contain all the genes necessary to produce an entire organism, and the egg cytoplasm can reprogram gene expression.

Question 2

Which of the following statements about gene regulation is TRUE?

Accepted Answer

Transcription initiation is often the most critical and rate-limiting step in regulating gene expression.

Question 3

DNA methylation most commonly occurs at which of the following sites in the genome?

Accepted Answer

Cytosine bases adjacent to guanine (CpG islands)

Question 4

What is the effect of methylation of CpG islands in the promoter region of a gene?

Accepted Answer

It decreases transcription of the gene.

Question 5

Which of the following best describes epigenetics?

Accepted Answer

Heritable changes in gene expression that do not involve changes to the DNA sequence.

Question 6

A child whose mother experienced famine during pregnancy is at increased risk for which of the following, according to epigenetic studies?

Accepted Answer

Increased risk of obesity, diabetes, and coronary heart disease.

Question 7

Which of the following is a plausible mechanism by which maternal care in rats influences the stress response in offspring?

Accepted Answer

Low maternal care increases methylation of the GR gene promoter, reducing GR expression.

Question 8

Which of the following best describes the relationship between Adverse Childhood Experiences (ACEs) and health outcomes, as depicted in the pyramid diagram?

Accepted Answer

ACEs are associated with increased risk of social, emotional, and cognitive problems, as well as disease and early death.

Question 9

The MT2A gene is expressed at low levels in all cells but is highly expressed in response to heavy metals. Which of the following best explains this regulation?

Accepted Answer

Basal expression is due to general transcription factors, while high expression requires metal-inducible transcription factors like MTF-1.

Question 10

Which of the following is TRUE regarding the expression of the pax6 gene in different tissues?

Accepted Answer

pax6 expression is regulated by tissue-specific enhancers and transcription factors such as Pbx1 and Meis.

Question 11

MITF is a transcription factor that binds to enhancer regions of tyrosinase genes. What is the expected effect of a loss-of-function mutation in MITF?

Accepted Answer

Decreased expression of tyrosinase genes.

Question 12

Which of the following best describes the function of a basic helix-loop-helix (bHLH) transcription factor, as shown in the image?

Accepted Answer

It binds to DNA and regulates gene expression by dimerizing and interacting with specific DNA sequences.

Question 13

Which of the following is a direct effect of environmental factors such as nutrition or stress on gene expression?

Accepted Answer

They can induce epigenetic changes such as DNA methylation, altering gene expression.

Question 14

Which of the following is a plausible explanation for why different cell types in a multicellular organism can have different functions despite having the same DNA?

Accepted Answer

Different cell types express different sets of genes due to regulation by transcription factors and epigenetic modifications.

Question 15

Which of the following best describes the role of enhancer elements in gene regulation?

Accepted Answer

Enhancers are DNA sequences that increase the transcription of associated genes when bound by specific transcription factors.

Question 16

A researcher observes that a gene is highly methylated in one tissue but unmethylated in another. What is the most likely consequence?

Accepted Answer

The gene will be silenced in the methylated tissue and expressed in the unmethylated tissue.

Question 17

Which of the following is a likely outcome of intergenerational transmission of Adverse Childhood Experiences (ACEs)?

Accepted Answer

Children of parents with high ACE scores are more likely to have high ACE scores themselves.

Question 18

Which of the following equations best represents the relationship between the probability of a child experiencing four or more ACEs and the parent's ACE score, based on the study cited?

Accepted Answer

$$P(	ext{child} \geq 4\, 	ext{ACEs}) = 3.25 	imes P(	ext{parent} \u003c 4\, 	ext{ACEs})$$

chap 17 pt 2

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