Homework #20: Mutations Quiz

What type of mutation involves the addition of an extra base in the DNA sequence?

• Deletion

• Substitution

• Insertion

• Missense

Answer explanation

An insertion mutation occurs when an extra base is added to the DNA sequence, which can lead to changes in the protein produced. This distinguishes it from deletion (removing a base) and substitution (replacing a base).

Tags

NGSS.HS-LS3-2

Which type of mutation shifts the reading frame of the genetic message?

• Substitution

• Frameshift

• Silent

• Missense

Answer explanation

A frameshift mutation occurs when nucleotides are added or deleted, altering the reading frame of the genetic message. This can lead to significant changes in the resulting protein, unlike substitutions or silent mutations.

Tags

NGSS.HS-LS3-2

What type of mutation results when a base is deleted from the DNA sequence?

• Substitution

• Missense

• Deletion

• Nonsense

Answer explanation

A deletion mutation occurs when one or more bases are removed from the DNA sequence. This type of mutation can lead to a shift in the reading frame, affecting the resulting protein. Therefore, the correct answer is 'Deletion'.

Tags

NGSS.HS-LS3-2

A mutation changes one base in the DNA but the amino acid stays the same. This is called a:

• Silent mutation

• Frameshift mutation

• Nonsense mutation

• Insertion mutation

Answer explanation

A silent mutation occurs when a change in the DNA sequence does not alter the amino acid produced. This is because multiple codons can code for the same amino acid, making the mutation 'silent' in terms of protein function.

Tags

NGSS.HS-LS3-2

Which of the following best describes a missense mutation?

• A base is added

• A base is deleted

• A base is substituted, causing a change in one amino acid

• A base is substituted, causing a stop codon

Answer explanation

A missense mutation occurs when a base is substituted, leading to a change in one amino acid in the protein sequence. This can affect the protein's function, unlike the other options which describe different types of mutations.

Tags

NGSS.HS-LS3-2

What happens during a nonsense mutation?

• A stop codon is introduced early

• A protein is made longer than normal

• A base is deleted but the protein stays the same

• One amino acid changes to another

Answer explanation

A nonsense mutation introduces a premature stop codon in the mRNA sequence, leading to the early termination of protein synthesis. This results in a truncated protein, which is why the correct answer is 'A stop codon is introduced early'.

Tags

NGSS.HS-LS3-2

Which of the following mutations is most likely to have NO effect on the final protein?

• Frameshift mutation

• Nonsense mutation

• Missense mutation

• Silent mutation

Answer explanation

A silent mutation does not change the amino acid sequence of a protein due to the redundancy in the genetic code. In contrast, frameshift, nonsense, and missense mutations typically alter the protein's structure or function.

Tags

NGSS.HS-LS3-2

A substitution mutation changes a codon from UAU to UAA. What kind of mutation is this? Hint UAA is a stop codon

• Silent

• Frameshift

• Nonsense

• Insertion

Answer explanation

The mutation changes UAU (tyrosine) to UAA, which is a stop codon. This results in premature termination of protein synthesis, classifying it as a nonsense mutation.

Tags

NGSS.HS-LS3-2

Which mutation is most likely to lead to a nonfunctional protein?

• Silent

• Missense

• Frameshift

• None

Answer explanation

A frameshift mutation alters the reading frame of the genetic code, often resulting in a completely different and nonfunctional protein. In contrast, silent mutations do not change the protein, and missense mutations may still produce functional proteins.

Tags

NGSS.HS-LS3-2

What type of mutation occurs when the sequence CTC becomes CAC, changing glutamic acid to valine in the hemoglobin protein?

• Nonsense

• Silent

• Missense

• Insertion

Answer explanation

The mutation from CTC to CAC results in a change from glutamic acid to valine in hemoglobin. This type of mutation, which alters the amino acid sequence, is called a missense mutation.

Tags

NGSS.HS-LS3-2