Genetic Mutations & Disorders
Comprehensive Test Review (Qns & Ans)
2025
1. Which of the following best describes a point mutation?
- A) A mutation that involves the insertion of multiple
nucleotide sequences
- B) A mutation that changes a single nucleotide base in the
DNA sequence
- C) A mutation that results in the deletion of an entire
chromosome
- D) A mutation that duplicates a large segment of DNA
- ANS: B) A mutation that changes a single nucleotide base in
the DNA sequence
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, - Rationale: A point mutation involves a change in a single
nucleotide base in the DNA sequence, which can lead to various
genetic disorders or have no effect at all.
2. What is the primary cause of cystic fibrosis?
- A) A bacterial infection
- B) A single-gene mutation in the CFTR gene
- C) An environmental toxin
- D) A chromosomal translocation
- ANS: B) A single-gene mutation in the CFTR gene
- Rationale: Cystic fibrosis is primarily caused by mutations
in the CFTR gene, which affect the production of a protein
involved in the regulation of salt and water transport in cells.
3. Which type of genetic mutation is most likely to result in a
frameshift mutation?
- A) Silent mutation
- B) Missense mutation
- C) Nonsense mutation
- D) Insertion or deletion mutation
- ANS: D) Insertion or deletion mutation
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, - Rationale: Insertion or deletion mutations can cause a
frameshift by altering the reading frame of the genetic code,
potentially leading to significant changes in the resulting protein.
Fill-in-the-Blank Questions
4. The __________ effect occurs when a new population is
established by a small number of individuals, leading to reduced
genetic diversity and increased likelihood of genetic disorders.
- ANS: Founder
- Rationale: The founder effect occurs when a new
population is established by a small number of individuals,
resulting in reduced genetic diversity and increased prevalence of
certain genetic disorders.
5. In genetic terminology, __________ refers to the complete
absence of a particular chromosome from the karyotype.
- ANS: Monosomy
- Rationale: Monosomy refers to the complete absence of a
particular chromosome from the karyotype, which can lead to
developmental abnormalities and genetic disorders.
6. The __________ gene is commonly mutated in individuals
with Huntington's disease, leading to progressive
neurodegenerative symptoms.
- ANS: HTT (huntingtin)
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