Quiz

Question 1: Which of the following statements accurately describes the role of histone H1 in chromatin structure?

A) H1 binds directly to DNA bases to stabilize nucleosomes.

B) H1 is responsible for histone acetylation.

C) H1 interacts with nucleosomes and linker DNA, stabilizing the chromatin fiber.

D) H1 prevents DNA methylation within CpG islands.

Question 2: During which phase of the cell cycle does DNA and histone synthesis primarily occur?

A) G1 phase

B) S phase

C) G2 phase

D) M phase

Question 3: What is the primary function of euchromatin?

A) It maintains genome stability during mitosis.

B) It condenses DNA into chromosomes during cell division.

C) It promotes transcriptional activity of genes.

D) It facilitates DNA replication.

Question 4: Which modification is associated with reversible changes in gene expression without altering the DNA sequence?

A) DNA methylation

B) Histone methylation

C) Histone acetylation

D) Histone deacetylation

Question 5: What is a characteristic feature of heterochromatin?

A) Light appearance under electron microscopy

B) Transcriptionally active state

C) Sterically accessible DNA

D) Highly condensed structure

Question 6: Which epigenetic modification is implicated in X chromosome inactivation?

A) Histone deacetylation

B) DNA methylation

C) Histone acetylation

D) Histone methylation

Question 7: How does histone deacetylation affect gene expression?

A) It activates transcription.

B) It loosens DNA coiling.

C) It tightens DNA coiling.

D) It has no effect on gene expression.

Question 8: Which histone modification is primarily associated with making DNA transcriptionally active?

A) Histone methylation

B) Histone acetylation

C) Histone deacetylation

D) Histone phosphorylation

Question 9: What is the role of histone H1 in relation to heterochromatin?

A) It promotes heterochromatin formation.

B) It binds to nucleosomes and linker DNA in heterochromatin.

C) It prevents DNA methylation in CpG islands.

D) It is absent in heterochromatin.

Question 10: Which DNA modification is often associated with gene silencing through promoter methylation?

A) Histone acetylation

B) DNA deacetylation

C) DNA methylation

D) Histone methylation

Question 11: What structural feature distinguishes heterochromatin from euchromatin under electron microscopy?

A) Presence of nucleosomes

B) Lighter appearance

C) Sterically accessible DNA

D) Highly condensed appearance

Question 12: Which cellular process is primarily influenced by histone acetylation?

A) DNA replication

B) RNA splicing

C) Protein translation

D) Gene expression

Question 13: What is the significance of mitochondrial DNA in relation to chromatin structure?

A) It lacks histones and exists in a circular form.

B) It undergoes histone acetylation for transcriptional activation.

C) It forms chromosomal structures during cell division.

D) It is embedded within nucleosomes for stability.

Question 14: Which condition is associated with dysregulated DNA methylation?

A) Cystic fibrosis

B) Huntington disease

C) Parkinson's disease

D) Fragile X syndrome