5.2 Gene Mutations

Biology

What does the phrase “reading frame” refer to?

The way nucleotides in DNA or RNA are grouped into codons for translation into proteins.

How many nucleotides make up one codon?

3 nucleotides

How many amino acids does one codon code for?

1 amino acid

In most cases, the ratio of codons to amino acids is # to #

1 to 1

What type of codon does not code for an amino acid?

Stop

If a gene is 15 nucleotides long, how many codons are there?

5

If a gene is 15 nucleotides long and the last codon is a STOP codon, how many amino acids are in the protein?

4

Substitution mutations can be classified as:

silent, missense, and nonsense

What type of mutation occurs when there is a change in the DNA sequence but the amino acid sequence remains the same?

Silent

What type of mutation occurs when there is a change in the DNA sequence and one amino acid changes as a result?

Missense

What types of mutations cause a frameshift mutation?

Insertion and Deletion

How is it possible that a deletion or insertion mutation can happen that does not cause a frameshift to occur?

If the number of nucleotides deleted or inserted is a multiple of three, the reading frame remains intact, preventing a frameshift mutation.

What type of mutation occurs when there is a change in the DNA sequence that results in a premature stop codon?

Nonsense

True or False: One codon can code for more than amino acid.

False

True or False: More than one codon may code for an amino acid.

True

What type of mutation occurs when one or more bases are added to a DNA sequence?

Insertion

What type of mutation occurs when one or more bases are deleted from a DNA sequence?

Deletion

Which type of mutation typically has no impact on protein structure and function?

Silent

Which type of mutation can lead to alternative variations of physical traits, such as eye colors?

Missense