$$\text{Gene density} = \frac{\text{Number of genes}}{\text{Genome size in base pairs}}$$

Question 1

Which of the following best explains why humans have a much larger genome than budding yeast, but only encode about four times as many genes?

Accepted Answer

Much of the human genome consists of non-protein-coding DNA, leading to a lower gene density.

Question 2

A scientist digests chromatin with MNase and observes a DNA ladder pattern on an agarose gel. What does this pattern most directly indicate?

Accepted Answer

The ordered array of nucleosomes protecting specific DNA fragments.

Question 3

Which histone variant is specifically found at centromeres and is essential for kinetochore formation?

Accepted Answer

CENP-A

Question 4

If the chromatin is a simple linear polymer, at a given position on the chromosome (n), which other numbered regions will it contact most frequently?

Accepted Answer

Regions adjacent to n, such as +1 and -1

Question 5

Which of the following best describes the function of SMC complexes such as cohesin in chromosome organization?

Accepted Answer

They hold and extrude DNA loops, contributing to structural organization and gene regulation.

Question 6

A patient with scleroderma is found to have antibodies against centromeric proteins. Which test is commonly used to detect such autoimmune disorders?

Accepted Answer

ANA (anti-nuclear antibody) test

Question 7

Which equation best represents the fold reduction in DNA length due to nucleosomal wrapping?

Accepted Answer

$$	ext{Fold reduction} = 7$$

Question 8

Which chromosome type is characterized by a centromere located near one end, resulting in a very short p arm?

Accepted Answer

Acrocentric

Question 9

In the Hi-C map, why is there a strong diagonal observed?

Accepted Answer

It indicates high contact probability between regions that are close together on the linear chromosome.

Question 10

Which of the following statements about centromeres is TRUE?

Accepted Answer

Most centromeres are composed of large repetitive DNA sequences, but the repeat sequences vary among species.

Question 11

Which of the following best explains the relationship between genome size and organism complexity?

Accepted Answer

Organisms with larger genomes have more non-protein-coding DNA, which may contribute to complexity.

Question 12

Which protein is most responsible for promoting higher order chromatin packaging beyond the nucleosome?

Accepted Answer

Histone H1

Question 13

Which of the following is a plausible consequence of defective condensin function during mitosis?

Accepted Answer

Mitotic chromosomes are fragile and often lag during chromosome segregation.

Question 14

Which equation would you use to calculate gene density in a genome?

Accepted Answer

$$	ext{Gene density} = \frac{	ext{Number of genes}}{	ext{Genome size in base pairs}}$$

Question 15

Which of the following best describes a topologically associated domain (TAD)?

Accepted Answer

A region of high contact probability, often forming loops and rosettes, separated by boundaries.

Question 16

Which of the following is a real-world application of understanding chromatin organization?

Accepted Answer

Diagnosing autoimmune diseases by detecting antibodies against nuclear proteins.

Question 17

Which of the following statements about nucleosome structure is correct?

Accepted Answer

The nucleosome core particle consists of a histone octamer and about 146 bp of DNA.

Question 18

Which of the following best describes the role of histone tail modifications?

Accepted Answer

They regulate chromatin structure and gene expression through post-translational modifications.

Question 19

Which equation would you use to estimate the total number of genes in a genome, given gene density and genome size?

Accepted Answer

$$	ext{Total genes} = 	ext{Gene density} 	imes 	ext{Genome size in base pairs}$$

Question 20

Which of the following is a characteristic feature of the budding yeast centromere?

Accepted Answer

It consists of a short (125 bp) DNA sequence associated with a single CENP-A nucleosome.

Chromatin Organization and Function: Structure, Packaging, and Regulation of the Genome

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