Question 1

A patient is found to have a mutation in a gene that is only present in their liver cells and not in their germ cells. Which type of mutation is this, and why will it not be passed on to their offspring?

Accepted Answer

It is a somatic mutation; it will not be passed on because only mutations in germ cells are heritable.

Question 2

Which of the following best describes a loss of function mutation?

Accepted Answer

A mutation that reduces or eliminates the activity of the gene product.

Question 3

A DNA sequence originally reads 5'-ATG GAA TGC-3'. After a mutation, it reads 5'-ATG GAG TGC-3'. What type of mutation has occurred, and what is the likely effect on the protein?

Accepted Answer

Missense mutation; it may change one amino acid in the protein, possibly altering its function.

Question 4

Which of the following scenarios would most likely result in a frameshift mutation?

Accepted Answer

Insertion of 2 nucleotides into a coding sequence.

Question 5

Why does the insertion or deletion of 3, 6, or 9 nucleotides not result in a frameshift mutation?

Accepted Answer

Because these numbers are multiples of 3, so the reading frame is preserved.

Question 6

A mutation changes a codon from UAU (tyrosine) to UAA (stop codon). What type of mutation is this, and what is its likely effect?

Accepted Answer

Nonsense mutation; it will result in a truncated, likely nonfunctional protein.

Question 7

Which of the following best describes a conditional mutation?

Accepted Answer

A mutation that only affects the phenotype under certain environmental conditions.

Question 8

A scientist uses restriction enzymes to analyze DNA samples from two individuals. The enzyme cuts at the sequence 5'-GAATTC-3'. Individual A's DNA is cut into three fragments, while Individual B's DNA is cut into four fragments. What does this suggest?

Accepted Answer

There is a difference in the DNA sequence at the restriction site between the two individuals.

Question 9

Which of the following is an example of a polygenic trait?

Accepted Answer

Human skin color, which is influenced by multiple genes.

Question 10

A mutation occurs spontaneously during DNA replication. Which of the following best describes this mutation?

Accepted Answer

It is a spontaneous mutation, arising without external influence.

Question 11

Which of the following best defines an allele?

Accepted Answer

A variant form of a gene at a particular locus on a chromosome.

Question 12

A person inherits a mutation that increases the activity of a protein, resulting in a new function not present in the wild-type protein. What type of mutation is this?

Accepted Answer

Gain of function mutation

Question 13

Which of the following best describes a phenotype?

Accepted Answer

The observable physical or biochemical characteristics of an organism.

Question 14

A mutation changes the DNA sequence but does not alter the amino acid sequence of the protein. What type of mutation is this, and why does it not affect protein function?

Accepted Answer

Silent mutation; the genetic code is degenerate, so some codons code for the same amino acid.

Question 15

Which of the following is an example of a multifactorial trait?

Accepted Answer

Type 2 diabetes, which is influenced by both genetic and environmental factors.

Question 16

Which of the following best describes a chromosomal rearrangement mutation?

Accepted Answer

A mutation involving large segments of DNA, such as inversions, translocations, duplications, or deletions.

Question 17

A researcher exposes cells to UV light, which causes thymine dimers and leads to mutations. What type of mutation is this?

Accepted Answer

Induced mutation

Question 18

Which of the following statements about restriction enzymes is correct?

Accepted Answer

They recognize specific DNA sequences and cut DNA at or near these sites.

Question 19

A patient has a mutation that changes a codon from GAA (glutamic acid) to GAG (also glutamic acid). What type of mutation is this, and what is the likely effect?

Accepted Answer

Silent mutation; no change in protein function.

Question 20

Which of the following best explains why a missense mutation might not affect protein function?

Accepted Answer

The substituted amino acid has similar properties to the original, so the protein's structure and function are preserved.

Chapter 15: Mutations, DNA, and Genetic Variation – Study Guide Walkthrough

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드