Q: Which of the following equations best represents the number of inheritable mutations per year in humans, given a genome size of $$3 \times 10^9$ base pairs and a mutation rate of 1/10^7$ per base pair per generation?

$$\text{Mutations/year} = 3 \times 10^9$ \times \frac{1}{10^7$}$$

Question 1

Which of the following best describes a missense mutation?

Accepted Answer

A mutation that changes one amino acid to another in the protein sequence.

Question 2

A patient is diagnosed with cystic fibrosis due to the deletion of three nucleotides in the CFTR gene, resulting in the loss of phenylalanine at position 508. What type of mutation is this?

Accepted Answer

In-frame deletion

Question 3

Which of the following equations best represents the probability of a single base pair mutation occurring in the human genome per generation?

Accepted Answer

$$P = \frac{1}{10^7$}$$

Question 4

Which chromosomal mutation is most likely to result in a gene being present in multiple copies, potentially leading to diseases such as Huntington’s disease?

Accepted Answer

Duplication

Question 5

A segment of DNA is cut out and reinserted in the reverse orientation. What type of chromosomal mutation is this?

Accepted Answer

Inversion

Question 6

Which of the following best explains why frameshift mutations are generally more harmful than point mutations?

Accepted Answer

Frameshift mutations can alter every amino acid downstream of the mutation site.

Question 7

A patient inherits a mutated BRCA1 gene. What is the most likely consequence?

Accepted Answer

Increased risk of developing breast, ovarian, and prostate cancers.

Question 8

Which of the following is a real-world example of a beneficial mutation in humans?

Accepted Answer

ApoA-1 Milano mutation providing resistance to atherosclerosis.

Question 9

Which gene family is most commonly mutated in cancers and acts as a molecular switch for cell growth and proliferation?

Accepted Answer

Ras family

Question 10

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

Accepted Answer

They act as brakes to prevent uncontrolled cell division.

Question 11

A DNA sequence originally reads $$5'	ext{-}GAG	ext{-}3' ($$Glu). A mutation changes it to $$5'	ext{-}GTG	ext{-}3' ($$Val). What type of mutation is this, and what disease is it associated with?

Accepted Answer

Missense mutation; sickle cell anemia

Question 12

Which of the following is NOT a possible cause of mutation?

Accepted Answer

Crossing over between non-homologous chromosomes during mitosis

Question 13

Which of the following best describes a translocation mutation?

Accepted Answer

A segment of one chromosome breaks off and attaches to a non-homologous chromosome.

Question 14

Which of the following equations best represents the number of inheritable mutations per year in humans, given a genome size of $$3 	imes 10^9$ base pairs and a mutation rate of 1/10^7$ per base pair per generation?

Accepted Answer

$$	ext{Mutations/year} = 3 	imes 10^9$ 	imes \frac{1}{10^7$}$$

Question 15

Which of the following is most likely to result from a nonsense mutation?

Accepted Answer

A protein with a premature stop codon

Question 16

Which of the following best explains why aging increases the mutation rate?

Accepted Answer

DNA repair mechanisms become less efficient, and more cell divisions occur over time.

Question 17

Which of the following is a direct result of a frameshift mutation in a protein-coding gene?

Accepted Answer

The reading frame of the mRNA is shifted, altering all downstream amino acids.

Question 18

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into mRNA, which is translated into protein.

Question 19

Which of the following is a plausible outcome if a proto-oncogene is mutated into an oncogene?

Accepted Answer

The cell divides uncontrollably, potentially leading to cancer.

Mutations and Cancer: Mechanisms, Types, and Implications in Cell Biology

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