Question 1

Which of the following best explains why Copy Cat and Rainbow, two cats with identical DNA, have different phenotypes?

Accepted Answer

Epigenetic modifications, such as DNA methylation, led to differences in gene expression.

Question 2

During nuclear transplantation in cows, why are the resulting calves genetically identical?

Accepted Answer

The donor cell's nucleus contains all the genetic instructions needed to form a complete organism.

Question 3

Which chemical modification is most directly associated with the silencing of gene expression at CpG islands?

Accepted Answer

DNA methylation

Question 4

What is the effect of DNA methylation at gene promoters?

Accepted Answer

It recruits proteins that condense chromatin, repressing transcription.

Question 5

Which of the following best describes heterochromatin?

Accepted Answer

Highly condensed, transcriptionally inactive regions of chromosomes.

Question 6

You treat a DNA sample with DNase and observe mostly long fragments after gel electrophoresis. What does this indicate about the chromatin state?

Accepted Answer

The DNA is mostly heterochromatin, which is resistant to DNase digestion.

Question 7

Which of the following is a key feature of epigenetic inheritance?

Accepted Answer

It involves heritable changes in gene expression without altering the DNA sequence.

Question 8

What is the main difference between intergenerational and transgenerational epigenetic inheritance?

Accepted Answer

The main difference lies in which generations are directly exposed to the original environmental factor.

Question 9

Which of the following statements about genomic imprinting is correct?

Accepted Answer

Differential methylation of DNA in males and females results in only one parental allele being transcriptionally active in the offspring.

Question 10

If a mouse inherits a loss-of-function Igf2 allele from its father, what will be the expected size of the offspring?

Accepted Answer

Small

Question 11

Which of the following best describes the role of histone acetylation in gene expression?

Accepted Answer

It relaxes chromatin, promoting gene transcription.

Question 12

Which enzyme is responsible for copying DNA methylation patterns during DNA replication?

Accepted Answer

DNA methyltransferase (DNMT)

Question 13

Which of the following is TRUE regarding the reversibility of epigenetic changes?

Accepted Answer

Epigenetic changes can be reversible, unlike most genetic mutations.

Question 14

A gene is transcriptionally active when its chromatin is in which state?

Accepted Answer

Euchromatin

Question 15

Which of the following best explains why methylation patterns must be reset during gamete formation?

Accepted Answer

To establish sex-specific imprinting patterns for the next generation.

Question 16

Which of the following is a direct consequence of DNA methylation at gene promoters?

Accepted Answer

Gene silencing

Question 17

Which of the following is NOT a characteristic of epigenetic changes?

Accepted Answer

They are always irreversible.

Question 18

Which of the following best describes the relationship between chromatin structure and gene expression?

Accepted Answer

Relaxed chromatin allows transcription factors to access gene promoters.

Question 19

If the maternal chromosome loses its imprinting at the Igf2 locus, what is the expected phenotype of the offspring?

Accepted Answer

Large size

Question 20

Which of the following is a real-world example of epigenetic regulation affecting phenotype?

Accepted Answer

Identical twins with different DNA methylation patterns showing different disease susceptibilities.

Epigenetics, Chromatin Structure, and Gene Regulation

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