Question 1

Which of the following best describes the primary function of centromeres during mitosis?

Accepted Answer

They provide attachment points for spindle microtubules via the kinetochore.

Question 2

A chromosome fragment generated by breakage that lacks a centromere is called:

Accepted Answer

Acentric fragment

Question 3

Which of the following is a direct consequence of the end replication problem in linear chromosomes?

Accepted Answer

Shortening of chromosomes with each cell division

Question 4

What is the main structural difference between centromeric and telomeric DNA sequences?

Accepted Answer

Centromeric DNA is highly repetitive satellite DNA (\u003e100 bp), while telomeric DNA consists of minisatellites (10-100 bp) and microsatellites (\u003c10 bp).

Question 5

Which enzyme solves the end replication problem by extending the 3' end of linear chromosomes?

Accepted Answer

Telomerase

Question 6

Which of the following best explains why telomerase is highly expressed in embryonic stem cells and germ cells?

Accepted Answer

These cells must maintain telomere length to avoid senescence and support unlimited divisions.

Question 7

Which of the following is NOT a component of a nucleosome?

Accepted Answer

Histone H1

Question 8

Which post-translational modification of histone tails neutralizes the positive charge of lysine residues?

Accepted Answer

Acetylation

Question 9

A mutation in the gene encoding the centromere-specific histone H3 (CENH3) would most likely result in:

Accepted Answer

Defective kinetochore assembly and chromosome missegregation

Question 10

Which of the following best describes the 'histone code' hypothesis?

Accepted Answer

A combination of histone modifications at a chromatin region determines the transcriptional activity of that region.

Question 11

Which of the following statements about nucleosome assembly during DNA replication is correct?

Accepted Answer

Both old and newly synthesized histones are randomly assembled onto daughter DNA strands.

Question 12

Which of the following modifications introduces a negative charge to histone tails?

Accepted Answer

Phosphorylation

Question 13

A researcher finds a chromatin region with highly acetylated histone H3 tails. What is the most likely effect on gene expression in this region?

Accepted Answer

Gene expression is likely activated due to increased chromatin accessibility.

Question 14

Which of the following best explains why telomere shortening is associated with cellular aging?

Accepted Answer

Short telomeres trigger DNA damage responses, leading to cellular senescence.

Question 15

Which of the following is a function of the T-loop structure at telomeres?

Accepted Answer

Protects chromosome ends from being recognized as double-strand breaks

Question 16

Which of the following statements about histone H1 is correct?

Accepted Answer

It binds to linker DNA and is required for higher-order chromatin structure.

Question 17

Which of the following best describes the organization of canonical histone genes in the human genome?

Accepted Answer

They are clustered to ensure coordinated expression during DNA replication.

Question 18

Which of the following is a plausible consequence of a mutation that prevents phosphorylation of histone H3 serine residues?

Accepted Answer

Failure to introduce negative charge, potentially affecting chromatin condensation and gene regulation

Question 19

Which of the following best explains why nucleosomes are resistant to nuclease digestion, while linker DNA is not?

Accepted Answer

Nucleosomes are protected by tightly bound histone proteins, while linker DNA is exposed.

Question 20

Which of the following is true regarding the conservation of histone proteins?

Accepted Answer

Histone H3 and H4 are highly conserved across eukaryotes.

Chromosome Structure and Chromatin Organization: Centromeres, Telomeres, and Nucleosomes

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