Question 1

What is the main problem that occurs when replicating linear chromosomes in eukaryotic cells?

Accepted Answer

The ends of linear chromosomes cannot be fully replicated, leading to progressive shortening with each cell division.

Question 2

Which of the following best describes a telomere and its sequence in humans?

Accepted Answer

A telomere is a repetitive DNA sequence at the end of chromosomes; its sequence is $$\mathrm{TTAGGG}.$$

Question 3

Does the telomere sequence code for a gene?

Accepted Answer

No, it is a non-coding repetitive DNA sequence.

Question 4

You have two cell populations in culture: Population A has been grown and propagated for 6 months, and Population B for 2 months. Which population will likely have shorter telomeres, assuming both are somatic cells?

Accepted Answer

Population A, because it has undergone more cell divisions.

Question 5

Fill in the blank: The more times a cell divides, the _______ its telomeres become.

Accepted Answer

shorter

Question 6

Which cells in the human body typically express telomerase?

Accepted Answer

Germ cells and cancer cells

Question 7

What is the function of telomerase in eukaryotic cells?

Accepted Answer

It adds repetitive DNA sequences to the ends of chromosomes, preventing telomere shortening.

Question 8

Why might an anti-telomerase drug be useful in treating cancer?

Accepted Answer

It would cause cancer cells to lose their telomeres and limit their ability to divide indefinitely.

Question 9

Which enzyme is responsible for extending telomeres in germ cells and some stem cells?

Accepted Answer

Telomerase

Question 10

During oogenesis and spermatogenesis, which enzyme helps prevent the loss of genetic information at chromosome ends?

Accepted Answer

Telomerase

Question 11

A researcher is studying a population of cancer cells and finds that they have unusually long telomeres. Which of the following is the most likely explanation?

Accepted Answer

The cells express high levels of telomerase, allowing them to maintain telomere length.

Question 12

Which of the following best explains why somatic cells age and eventually stop dividing?

Accepted Answer

Their telomeres shorten with each division, eventually triggering cell senescence.

Question 13

If a mutation caused somatic cells to express telomerase at high levels, what would be a likely consequence?

Accepted Answer

The cells could divide indefinitely, increasing the risk of cancer.

Question 14

Which of the following equations best represents the relationship between the number of cell divisions ($$n) $$and telomere length ($$L$$), assuming a constant loss per division ($$d) $$and initial length $$L_0$$?

Accepted Answer

$$L = L_0$ - n 	imes d$$

Question 15

A patient is treated with a drug that inhibits telomerase. Which cell type is most likely to be affected by this treatment?

Accepted Answer

Cancer cells

Question 16

Which of the following statements about telomeres and cancer is correct?

Accepted Answer

Cancer cells often reactivate telomerase, allowing unlimited cell division.

Question 17

A scientist observes that a certain cell type does not express telomerase and has progressively shorter telomeres with each division. What type of cell is this most likely to be?

Accepted Answer

Somatic cell

Question 18

Which of the following is a potential risk of using telomerase-activating therapies to treat age-related diseases?

Accepted Answer

Increased risk of cancer due to unlimited cell division.

Question 19

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

Accepted Answer

They protect chromosome ends from degradation and prevent them from being recognized as DNA breaks.

Telomeres, Telomerase, and the End Replication Problem in Eukaryotic Cells

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