Genetic Mutations

Question 1

What is a mutation, and what is it responsible for?

Answer 1

A mutation is an unintentional change or variation in genetic structure, and it is ultimately responsible for the broad diversity of genes.

Question 2

How do mutations arise?

Answer 2

Usually either through errors during DNA replication or recombination or the addition of an incorrect nucleotide (Campbell).

Question 3

What are the two major categories of mutations?

Answer 3

Large-scale mutations and small-scale mutations

Question 4

What are large-scale mutations, and what do they affect?

Answer 4

Large-scale mutations are chromosomal rearrangements that affect long segments of DNA (Campbell)

Question 5

What are the two major categories of small-scale mutations?

Answer 5

Single nucleotide-pair substitutions and Nucleotide-pair insertions or deletions

Question 6

What are the different types of single nucleotide-pair substitutions?

Answer 6

Silent, Missense, and Nonsense Mutations

Question 7

What is a silent mutation, and what observable effect does it have on phenotypes?

Answer 7

A silent mutation is a change in a nucleotide pair that transforms one codon into another, but due to the redundancy of genetic code, that mutation is translated into the same amino acid (CAmpbell). Therefore, there is no observable effect on the phenotype.

Question 8

What is a missense mutation?

Answer 8

Missense mutations are a type of single nucleotide-pair substitution that changes the produced amino acid into a different one.

Question 9

What is a nonsense mutation and what does it lead to?

Answer 9

A nonsense mutation is a point mutation that also changes a codon for an amino acid into a stop codon. It most often leads to nonfunctional proteins.

Question 10

What are insertions/deletions?

Answer 10

Additions or subtractions of nucleotide pairs in a gene.

Question 11

What is a frameshift mutation?

Answer 11

Frameshift mutations occur whenever the number of nucleotides inserted or deleted is not a multiple of three, and as a result, nucleotides will be improperly grouped into incorrect codons (Campbell).

Question 12

What are mutagens?

Answer 12

Mutagens are some sort of agent, either physical or chemical, that cause genetic mutations.

Question 13

Name the mutation: A mutation changes a TCA codon coding for Ser to TCG, which also codes for Ser

Answer 13

Silent Mutation

Question 14

Name the mutation: A mutation changes a TCA codon coding for Ser to CCA coding for Pro.

Answer 14

Missense Mutation

Question 15

Name the mutation: A mutation changes a TCA codon coding for Ser to TAA coding for stop

Answer 15

Nonsense Mutation

Question 16

Name the mutation: These two mutations change every amino acid in the protein beyond the point where it occurs

Answer 16

Insertions and Deletions that caused a frameshift mutation

Question 17

What is a point mutation?

Answer 17

A point mutation is a mutation that influences a single nucleotide in genes.