Question 1

Which type of mutation results in a change in the DNA sequence but does NOT alter the amino acid sequence of the protein?

Accepted Answer

Silent mutation

Question 2

A mutation changes a codon from $$	ext{AGC} ($$Serine) to $$	ext{UGA} ($$Stop). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 3

Which of the following best describes a frameshift mutation?

Accepted Answer

An insertion or deletion that alters the reading frame of the gene

Question 4

Why are somatic mutations more likely to occur than germline mutations?

Accepted Answer

Somatic cells undergo many more cell divisions and are less protected from environmental factors

Question 5

Which of the following is TRUE about germline mutations?

Accepted Answer

They are inherited and can affect the entire organism

Question 6

A spontaneous mutation is most likely caused by which of the following?

Accepted Answer

DNA polymerase errors during replication

Question 7

Which chemical change in DNA bases can lead to spontaneous mutations due to anomalous base pairing?

Accepted Answer

Tautomeric shift

Question 8

Induced mutations are most commonly associated with which of the following?

Accepted Answer

Exposure to mutagens such as UV light or chemicals

Question 9

In a forward genetics approach, what is the starting point for investigation?

Accepted Answer

Mutant phenotype

Question 10

Which DNA repair mechanism is most accurate for repairing double-strand breaks and requires a sister chromatid as a template?

Accepted Answer

Homologous recombination repair (HR)

Question 11

Why can homologous recombination repair (HR) only occur after S phase?

Accepted Answer

Because a sister chromatid is only available after DNA replication

Question 12

Which DNA repair pathway is error-prone and often results in deletions or additions of nucleotides?

Accepted Answer

Nonhomologous end joining (NHEJ)

Question 13

A patient is exposed to X-rays and develops a mutation in a skin cell. Which type of mutation is this, and will it be inherited?

Accepted Answer

Somatic mutation; not inherited

Question 14

A DNA sequence undergoes a single base deletion. What is the most likely consequence for the protein encoded by this gene?

Accepted Answer

A frameshift mutation

Question 15

Which equation best represents the probability of a mutation occurring per cell division, given a mutation rate $$\mu$$ and $$n$$ cell divisions?

Accepted Answer

$$P = \mu 	imes n$$

Question 16

A researcher uses CRISPR to create a double-strand break in a gene. Which repair pathway is most likely to introduce mutations at the break site?

Accepted Answer

Nonhomologous end joining (NHEJ)

Question 17

Which of the following best explains why geneticists use mutagens in laboratory experiments?

Accepted Answer

To study gene function by inducing mutations

Question 18

A mouse with a mutant phenotype is studied to identify the gene responsible for the trait. Which genetic approach is being used?

Accepted Answer

Forward genetics

Question 19

Which of the following is a common misconception about DNA repair mechanisms?

Accepted Answer

All DNA repair mechanisms are equally accurate

Question 20

If a mutation occurs in a non-coding region of DNA, what is the most likely effect?

Accepted Answer

Change in the expression of a gene

Chap 15

Study Guide - Practice Questions