Q: Which equation best represents the probability of a cell acquiring two independent mutations, each occurring at a rate of $$1 \times 10$$^{-5}$$?

$$(1 \times 10$$^{-5}$$) \times (1 \times 10$$^{-5}$$) = 1 \times 10$$^{-10}$$

Question 1

Which of the following best describes the 'multi-hit model' for carcinogenesis?

Accepted Answer

Cancer results from the accumulation of multiple mutations in key genes within a single cell.

Question 2

A patient inherits a germline mutation in the BRCA1 gene. What is the most likely consequence?

Accepted Answer

They have an increased risk of developing breast and ovarian cancer due to impaired DNA repair.

Question 3

Which of the following is a property commonly shared by cancer cells but not normal cells?

Accepted Answer

Loss of contact inhibition and the ability to grow in piles

Question 4

A single missense mutation in the Ras gene (G12V) leads to which of the following outcomes?

Accepted Answer

Ras protein remains active, continuously signaling cell division even without growth factors.

Question 5

Which equation best represents the probability of a cell acquiring two independent mutations, each occurring at a rate of $$1 	imes 10$$^{-5}$$?

Accepted Answer

$$(1 	imes 10$$^{-5}$$) 	imes (1 	imes 10$$^{-5}$$) = 1 	imes 10$$^{-10}$$

Question 6

Which of the following best explains why most cancer deaths are due to metastasis?

Accepted Answer

Metastatic tumors spread to vital organs, disrupting their function and making treatment more difficult.

Question 7

What is the role of the p53 protein in the cell cycle?

Accepted Answer

It acts as a transcription factor that activates genes for cell cycle arrest, DNA repair, or apoptosis in response to DNA damage.

Question 8

Which of the following statements about oncogenes is correct?

Accepted Answer

Oncogenes are mutated forms of proto-oncogenes and act in a dominant manner.

Question 9

A child presents with tumors in both eyes, and there is a family history of retinoblastoma. According to Knudson's two-hit hypothesis, what is the most likely explanation?

Accepted Answer

The child inherited one defective copy of the RB gene and acquired a second mutation somatically.

Question 10

Which of the following is a real-world example of a carcinogen that acts as a mutagen?

Accepted Answer

Ultraviolet (UV) radiation from sunlight causing skin cancer

Question 11

Why do most differentiated somatic cells have a limited replicative potential?

Accepted Answer

They lack expression of the telomerase gene, leading to telomere shortening.

Question 12

Which of the following best describes the function of tumor suppressor genes?

Accepted Answer

They prevent uncontrolled cell growth by requiring both alleles to be inactivated for cancer to develop.

Question 13

A woman with a BRCA2 mutation has what probability of developing ovarian cancer by age 70?

Accepted Answer

$$15\%$$

Question 14

Which of the following is a hallmark of cancer cells that allows them to grow beyond a small size?

Accepted Answer

Sustained angiogenesis

Question 15

What is the main reason why HPV vaccination is recommended for young people?

Accepted Answer

It prevents infection by HPV strains that cause most cases of cervical cancer.

Question 16

Which of the following best explains why cancer is considered a genetic disease?

Accepted Answer

Most cancers are caused by mutations in the genome, either somatic or germline.

Question 17

Which of the following best describes the effect of a loss-of-function mutation in a DNA repair gene?

Accepted Answer

It increases the mutation rate, predisposing cells to cancer.

Question 18

A person with xeroderma pigmentosum (XP) is at high risk for cancer because:

Accepted Answer

They cannot repair DNA damage caused by UV light due to mutations in nucleotide excision repair genes.

Question 19

Which of the following is NOT a common property of cancer cells?

Accepted Answer

Sensitivity to anti-growth signals

Question 20

Which of the following best explains why avoiding tobacco is the single most effective lifestyle decision to prevent cancer?

Accepted Answer

Tobacco contains carcinogens that are mutagens, increasing the risk of multiple cancers.

Genetics of Cancer: Mechanisms, Mutations, and Cellular Pathways

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