Question 1

Which type of DNA mutation involves the replacement of one nucleotide with another, without changing the overall length of the DNA sequence?

Accepted Answer

Substitution

Question 2

A mutation changes a codon from GAA to GAG, both of which code for glutamic acid. What type of mutation is this?

Accepted Answer

Silent mutation

Question 3

Which of the following best describes a frameshift mutation?

Accepted Answer

A mutation caused by insertion or deletion of nucleotides not in multiples of three, altering the reading frame

Question 4

A point mutation results in a codon that now codes for a stop signal instead of an amino acid. What is the consequence for the protein product?

Accepted Answer

The protein will be truncated and likely nonfunctional

Question 5

Which equation represents the number of possible reading frames for a double-stranded DNA molecule?

Accepted Answer

$N = 2 	imes 3$

Question 6

A mutation in a non-coding region of DNA is most likely to have which effect?

Accepted Answer

It will likely have a neutral effect

Question 7

Which of the following mutations is most likely to result in a loss of protein function?

Accepted Answer

Nonsense mutation

Question 8

A patient has a genetic disorder caused by a single nucleotide deletion in a coding region. What is the most likely molecular consequence?

Accepted Answer

A frameshift mutation

Question 9

Why do most DNA mutations have neutral consequences?

Accepted Answer

Because many DNA changes are in places that do not affect gene function

Question 10

Which of the following best explains why some amino acid substitutions do not affect protein function?

Accepted Answer

Some substitutions occur in regions of the protein that are not critical for function

Question 11

A missense mutation changes a codon from AAA (lysine) to GAA (glutamic acid). What is the potential impact on the protein?

Accepted Answer

The protein may have altered function depending on the role of the substituted amino acid

Question 12

Which of the following is NOT a type of point mutation?

Accepted Answer

Duplication

Question 13

If a mutation changes the primary structure of a protein, what is the most likely consequence?

Accepted Answer

Altered folding and possibly altered function

Question 14

Which of the following scenarios best illustrates a nonsense mutation?

Accepted Answer

A codon for tryptophan is changed to a stop codon

Question 15

A mutation in the DNA sequence leads to a change in the mRNA, which then alters the amino acid sequence of a protein. Which level of protein structure is directly affected first?

Accepted Answer

Primary structure

Question 16

Which of the following is the correct sequence of events for how a DNA mutation can affect protein function?

Accepted Answer

Mutation in DNA → altered mRNA → altered amino acid sequence → altered protein folding/function

Question 17

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

Accepted Answer

Nonsense mutation; protein will be truncated

Question 18

Which of the following best describes why some mutations are classified as 'important'?

Accepted Answer

They result in changes that affect protein function or cause disease

Question 19

If a mutation occurs in a region of DNA that codes for the active site of an enzyme, what is the most likely outcome?

Accepted Answer

The enzyme may lose its catalytic activity

Question 20

Which of the following statements about frameshift mutations is correct?

Accepted Answer

Frameshift mutations can drastically alter the amino acid sequence downstream of the mutation

Classification and Impact of Mutations in Genetics

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