Mutations

Point Mutations

Multiple Choice

Point mutations are minor DNA changes that occur during

• DNA replication

• crossing over

• meiosis

#1:

Mutated DNA: T A C A C C T T A G C G A C G A C T

Transcribe and translate the mutated DNA

Original DNA: T A C A C C T T G G C G A C G A C T

A U G - U G G - A A C - C G C - U G C - U G A

MET - TRP - ASN - ARG - CYS - (stop)

Multiple Choice

Mutation #1 is a _____ mutation.

• silent

• missense

• nonsense

#2:

Mutated DNA: T A C A C C T G G G C G A C G A C T

Transcribe and translate the mutated DNA

Original DNA: T A C A C C T T G G C G A C G A C T

A U G, U G G, A A C, C G C, U G C, U G A

Examples:

●Sickle cell anemia

●Orange v white tiger fur

MET - TRP - ASN - ARG - CYS - (stop)

Multiple Choice

Mutation #2 is a _____ mutation.

• silent

• missense

• nonsense

The SLC45A2 gene makes a protein of the same name, which consists of 560 amino acids. A single mutation in the gene—a change in just one DNA letter—switches one of those 560 amino acids from an alanine to a valine. This distorts the protein’s shape, and potentially prevents it from taking part in the creation of red-yellow melanin. Every white tiger has two copies of this mutated gene, and can only make the distorted protein. That’s all it takes to change their coats from orange to white.

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(N.d.). Retrieved from https://www.cell.com/current-biology/fulltext/S0960-9822(13)00495-8?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982213004958%3Fshowall%3Dtrue

Tiger Fur

Chromosome Mutations

Karyotype

= a photo of an organism’s chromosomes arranged

✔ in order
✔ with their homologous partners

Chromosome Disorders

changes to a single chromosome

Multiple Choice

Chromosome mutations like these occur during

• DNA replication in interphase

• crossing over in meiosis

• anaphase in meiosis

Nondisjunction

missing or extra chromosome

Multiple Choice

Losing or gaining an extra chromosome occur during

• DNA replication in interphase

• crossing over in meiosis

• anaphase in meiosis