Question 1

Which of the following best describes a frameshift mutation, and what is its likely effect on the resulting protein?

Accepted Answer

A mutation that deletes or inserts one or two nucleotides, shifting the reading frame and usually resulting in a nonfunctional protein.

Question 2

A patient is found to have sickle cell anemia. Which specific DNA mutation is responsible for this condition?

Accepted Answer

A single nucleotide substitution from A to T in the beta-globin gene, resulting in a change from glutamic acid to valine.

Question 3

Which of the following best explains why individuals with the CCR5-Δ32 mutation are resistant to HIV infection?

Accepted Answer

The mutation results in a frameshift, producing a nonfunctional CCR5 protein that HIV cannot use to enter cells.

Question 4

Which type of genetic variation is most useful for DNA fingerprinting in forensic science?

Accepted Answer

Variable number tandem repeats (VNTRs)

Question 5

A child is born with Down syndrome. Which chromosomal abnormality is responsible for this condition?

Accepted Answer

47, +21 (trisomy 21)

Question 6

Which DNA repair mechanism is responsible for removing and replacing a single incorrect base and its sugar from the DNA strand?

Accepted Answer

Base excision repair

Question 7

A population has a high frequency of individuals with multiple copies of the AMY1 gene. What dietary habit is most likely associated with this genetic pattern?

Accepted Answer

A diet high in starch

Question 8

Which of the following best describes a nonsense mutation?

Accepted Answer

A mutation that changes a codon to a stop codon, resulting in a truncated protein.

Question 9

Which of the following is a likely consequence of nondisjunction during meiosis?

Accepted Answer

Some gametes will have an extra chromosome, and some will be missing a chromosome.

Question 10

Which of the following statements about transposable elements is correct?

Accepted Answer

They can move from one location in the genome to another and may be beneficial or harmful.

Question 11

A patient’s DNA sample shows a single nucleotide change that does not alter the amino acid sequence of the encoded protein. What type of mutation is this?

Accepted Answer

Synonymous (silent) mutation

Question 12

Which of the following best explains why RNA viruses, such as HIV, have higher mutation rates than DNA viruses?

Accepted Answer

RNA polymerases lack proofreading ability, leading to more replication errors.

Question 13

Which of the following is an example of a copy number variation (CNV)?

Accepted Answer

A region of a chromosome that is present in two copies in some individuals and only one copy in others.

Question 14

A person with the genotype 47, XXY is likely to have which syndrome and what are some of its features?

Accepted Answer

Klinefelter syndrome; tall stature, poor beard growth, and small testes

Question 15

Which DNA repair mechanism is most likely to fix a thymine dimer caused by UV light?

Accepted Answer

Nucleotide excision repair

Question 16

Which of the following best describes the process of gene duplication and divergence?

Accepted Answer

A gene is duplicated, and the copies accumulate mutations, potentially leading to new functions.

Question 17

A restriction enzyme is used to analyze DNA samples from two individuals. The resulting gel shows different banding patterns. What is the most likely explanation?

Accepted Answer

There is a restriction fragment length polymorphism (RFLP) between the individuals.

Question 18

Which of the following is a likely outcome of an unbalanced chromosomal translocation?

Accepted Answer

One chromosome segment is present in three copies, and another segment is present in only one copy.

Question 19

Which of the following best describes the difference between somatic and germ-line mutations?

Accepted Answer

Somatic mutations occur in body cells and are not passed to offspring, while germ-line mutations occur in reproductive cells and can be inherited.

Mutations and Genetic Variation: Mechanisms, Effects, and Detection

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