Deck 5: Epigenetic Influences on Gene Expression

Question 1

How does histone modification alter gene expression?

A)Modified histones result in increased DNA methylation, which increases the transcription of genes in that area.
B)In areas where histones are modified, the DNA is more tightly wound, and genes are not transcribed.
C)Histone modification results in an increase in microRNA production, which inhibits gene expression by preventing translation.
D)Histone modification results in an increase in microRNA production, which promotes gene expression by enhancing translation.

Answer 1

In areas where histones are modified, the DNA is more tightly wound, and genes are not transcribed.

Question 2

Which term or phrase is used to describe the ability of the environment to cause different phenotypes to develop from the same genotype?

A)Developmental plasticity
B)Histone modification
C)Phenotype variability
D)Nutrigenomics

Answer 2

Developmental plasticity

Question 3

Which statement regarding the influence of epigenetic changes on gene expression is always true?

A)The change must be inherited from the parent of the same gender as the child for expression to be affected.
B)Although gene expression is changed by inheriting these changes, the gene's DNA sequence remains unaffected.
C)Epigenetic changes must first occur in the parental somatic cells in order to be inherited.
D)These changes occur throughout the genome rather than in the area of any single specific gene.

Answer 3

Although gene expression is changed by inheriting these changes, the gene's DNA sequence remains unaffected.

Question 4

How is eating a diet high in broccoli thought to reduce cancer risk?

A)Increasing the excretion rate of foods known to be methyl donors
B)Increasing histone acetylation, turning on anticancer genes
C)Decreasing the rate of microDNA synthesis and activity
D)Decreasing the exposure of carcinogens to nuclear DNA

Question 5

Which statement about the microbiome is true?

A)The microbiome does not undergo further changes after development is complete.
B)With aging, its influence on health is reduced.
C)The microbiome is necessary for good health.
D)Identical twins have identical microbiomes.

Question 6

How is alcohol consumption thought to increase methylation in cancer suppressor genes to increase the risk for head and neck cancer?

A)Preventing DNA repair
B)Enhancing cell division
C)Acting as a methyl donor
D)Activating select oncogenes

Question 7

What part of a chromosome's DNA is altered by histone modification?

A)Complementary base pairing
B)Attachment of phosphate groups
C)Development of telomeric "caps"
D)The degree of tension in helical tightness

Question 8

What would be the expected result when the area around an oncogene is hypomethylated?

A)Cell division increases; cancer risk increases.
B)Cell division increases; cancer risk decreases.
C)Cell division decreases; cancer risk decreases.
D)Cell division decreases; cancer risk increases.

Question 9

By which mechanism does microRNA "silence" gene expression?

A)Preventing cytoplasm from coming into contact with the gene
B)Surrounding mRNA and preventing attachment of ribosomes
C)Binding to mRNA and keeping it double stranded
D)Substituting a thymine for uracil

Question 10

In fragile X syndrome, only noncoding regions within the gene for a protein that directs and maintains brain development are heavily methylated, resulting indecreasedcognitive ability and behavioral problems. What is the most likely mechanism of this abnormal expression?

A)Increased microRNA molecules reducing the synthesis of the gene product
B)Failure of the methylated regions to undergo translation
C)Suppression of the "splicing out" action for introns
D)Suppression of promoter function

Question 11

What would be the expected outcome for a person who has a normal gene allele and an abnormal gene allele for insulin and the area around the abnormal gene allele isheavily methylated?

A)Normal insulin is produced in normal amounts.
B)Normal insulin is produced in lower-than-normal amounts.
C)Abnormal insulin is produced in normal amounts.
D)Abnormal insulin is produced in higher-than-normal amounts.