Question 1

Which of the following best describes the function of the shelterin complex at chromosome ends?

Accepted Answer

It protects chromosome ends by forming a T-loop structure.

Question 2

A mutation disrupts the cooperative binding of shelterin proteins at the 3’ telomere. Which cellular outcome is most likely?

Accepted Answer

Loss of T-loop formation, leading to chromosome end instability.

Question 3

Which equation best represents the relationship between nucleosome repeat length ($$NRL$$), core DNA ($$CD$$), and linker DNA ($$LD$$)?

Accepted Answer

$$NRL = CD + LD$$

Question 4

In a scenario where histone H1 is depleted from chromatin, what is the most likely effect on DNA organization?

Accepted Answer

Chromatin becomes less compact, increasing accessibility for transcription.

Question 5

A patient presents with a genetic disorder characterized by rapid telomere shortening. Which protein complex is most likely dysfunctional?

Accepted Answer

The shelterin complex

Question 6

Which of the following statements about chromatin structure is correct?

Accepted Answer

Euchromatin is less condensed and generally transcriptionally active.

Question 7

If the nucleosome repeat length ($$NRL) in a $$cell is measured as 200 bp and the core DNA ($$CD) is 147 bp$$, what is the length of the linker DNA ($$LD$$)?

$$NRL = CD + LD$$

Accepted Answer

$$LD = 53 	ext{ bp}$$

Question 8

Which real-world scenario best illustrates the importance of chromatin remodeling in gene expression?

Accepted Answer

A cancer cell upregulates oncogenes by increasing chromatin accessibility.

Question 9

Which of the following is a direct consequence of defective T-loop formation at telomeres?

Accepted Answer

Activation of DNA damage response pathways.

Question 10

A researcher is studying the effect of histone modifications on chromatin structure. Which modification is most likely to result in increased gene expression?

Accepted Answer

Histone acetylation

Question 11

Which formula correctly represents the calculation of telomere length ($$TL) $$after $$n$$ cell divisions, assuming a loss of $$l$$ base pairs per division and an initial length $$TL_0$$?

Accepted Answer

$$TL = TL_0$ - n 	imes l$$

Question 12

Which of the following best explains why telomeres are necessary for chromosome stability?

Accepted Answer

They prevent chromosomes from fusing with each other.

Question 13

A scientist observes that a cell line has unusually short linker DNA between nucleosomes. What is the most likely effect on chromatin structure?

Accepted Answer

Chromatin will be more condensed, reducing gene expression.

Question 14

Which protein is NOT a component of the shelterin complex?

Accepted Answer

Histone H1

Question 15

A cell with defective shelterin complex fails to form T-loops at telomeres. Which process is most likely to be activated as a result?

Accepted Answer

Non-homologous end joining (NHEJ)

Question 16

Which of the following is a plausible outcome of increased histone H1 binding to chromatin?

Accepted Answer

Chromatin becomes more condensed, reducing transcription.

Question 17

Which scenario best illustrates the application of chromatin structure knowledge in medicine?

Accepted Answer

Developing drugs that inhibit histone deacetylases to treat cancer.

Question 18

Which of the following is a direct function of the shelterin complex?

Accepted Answer

Preventing telomere ends from being recognized as DNA breaks.

Question 19

A cell is exposed to a drug that disrupts nucleosome formation. Which outcome is most likely?

Accepted Answer

DNA becomes more susceptible to damage and less regulated in expression.

Question 20

Which formula would you use to calculate the total number of nucleosomes ($$N) in a $$chromosome of length $$L (in bp$$), given nucleosome repeat length $$NRL$$?

Accepted Answer

$$N = \frac{L}{NRL}$$

DNA Organization and Chromatin Structure

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