Mutations

Question 1

Loss in function mutation

Answer 1

Results in partially or fully nonfunctional gene product

Question 2

Null

Answer 2

Fully nonfunctional

Question 3

Gain of function mutation

Answer 3

Causes gene product to have more activity

Question 4

Spontaneous mutation

Answer 4

Results from mistakes during replication

Question 5

Induced mutation

Answer 5

Caused by mutagens (radiation, drugs, intercalating agents, etc.)

Question 6

Mutation induced by radiation

Answer 6

Interaction with water, which then attacks DNA

Question 7

Mutation induced by drugs

Answer 7

Causes oxidative stress to DNA

Question 8

Mutation caused by intercalating agents

Answer 8

Intercalating agents insert themselves into DNA

Question 9

Mutation caused by base analogs

Answer 9

Base analogs look like DNA and nucleotides, but don’t have their functions

Question 10

Somatic mutation

Answer 10

Not passed onto next generation

Question 11

Germ-line mutation

Answer 11

Transmitted onto future generations

Progeny has mutation in both somatic and germ-line cells

Question 12

Base pair substitutions

Answer 12

Change 1 base pair to another base pair

Question 13

Base pair insertions/deletions

Answer 13

Addition or removal of a base pair

Question 14

Transition mutation

Answer 14

Changing from 1 purine-pyrimidine base pair to another pur-pyr base pair

Question 15

Transversion mutation

Answer 15

Change from pur-pyr to pyr-pur or pyr-pur to pur-pyr

Question 16

Missense mutation

Answer 16

A change in a codon so that a different amino acid is added to the polypeptide
Phenotypic change depends on amount of difference from original

Question 17

Nonsense mutation

Answer 17

Change from functional codon to stop codon

Often severe phenotypic effect, but effect depends on where mutation is and what amino acid is changed

Question 18

Silent mutation

Answer 18

Change 1 codon for 1 amino acid to a different codon for the same amino acid

Question 19

Neutral mutation

Answer 19

Change amino acid to another amino acid with similar chemical properties
Mild or no phenotypic effect

Question 20

Frameshift mutation

Answer 20

Addition or deletion of 1 or more base pairs changes open reading frame
Missense or stop results

Question 21

Trinucleotide repeat expansion

Answer 21

Areas of genome have 3 nucleotides repeated many times in a row
If occurs in coding region, long stretches of an amino acid repeat themselves

Question 22

Forward mutation

Answer 22

Change wild-type allele to mutant allele

Question 23

Reverse mutation

Answer 23

Change to pre-mutation state

Change mutant allele so that the phenotype becomes more like wild-type

Question 24

Suppressor mutation

Answer 24

Masks the phenotype

At different site than original mutation

Question 25

Intragenic suppressors

Answer 25

Suppressor mutation within the same gene (“corrects” other mutation)
Ex: deletion after insertion

Question 26

Intergenic suppressors

Answer 26

Suppressor mutation in another gene

Ex: mutation in tRNA anticodon after mutation in gene