Mutations

Question 1

mutations always change ________

Answer 1

genotype of organism

Question 2

genotype

Answer 2

complement of genes organism possesses

Question 3

phenotype

Answer 3

physical expression of genes

appearance, chemical and structural characteristics of individuals

Question 4

effect of mutation on organism depends on

Answer 4

where it occurs and how much the protein changes

Question 5

sickle cell anemia

Answer 5

1 DNA base change in gene for hemoglobin changes 1 amino acid
glutamate (GLU) is replaced by valine (VAL)

Question 6

neutral mutations

Answer 6

do not affect survival

may occur in unexpressed regions of DNA

Question 7

beneficial mutations

Answer 7

rare

antibiotics resistance in bacteria

Question 8

2 forms of mutations

Answer 8

1. spontaneous

2. induced

Question 9

spontaneous mutations

Answer 9

occur naturally during replication or form as misalignment deletions

Question 10

induced mutations

Answer 10

caused by mutagens

Question 11

3 types of mutagens

Answer 11

1. chemical
2. physical
3. biological

Question 12

chemical mutagens

Answer 12

chemicals mimic DNA bases or alter normal bases
AZT- mimics thymine
acyclovir- mimics guanine
aminopurine- mimics adenine
bromouracil- mimics thymine; binds guanine not adenine
nitrous acid- alters adenine to bind cytosine not thymine

Question 13

physical mutagens

Answer 13

uv light and ionizing radiation

Question 14

uv light

Answer 14

non ionizing, non penetrating rays

cause thymine dimers in DNA of skin from sunburn

Question 15

thymine dimers

Answer 15

adjacent thymines bind laterally

may cause melanoma

Question 16

xeroderma pigmentosum

Answer 16

genetic disease

tumors in response to uv

Question 17

ionizing radiation

Answer 17

penetrates barriers

damages DNA

Question 18

biological mutagens

Answer 18

transposons
“jumping genes”
control own movement- move around genome
cause mutations when inserted into other genes

Question 19

5 mutation patterns

Answer 19

1. base substitution
2. frameshift
3. inversions
4. duplications
5. translocation

Question 20

base substitution

Answer 20

point mutation
1 DNA base changed to another
a. missense
b. silent
c. nonsense

Question 21

missense mutation

Answer 21

changes codon at 1st or 2nd DNA base
alters codon meaning to change amino acid
alters amino acid sequence of protein- may change protein function
sickle cell anemia

Question 22

silent mutation

Answer 22

changes 3rd base of codon
usually codes for same amino acid
usually no effect on protein function

Question 23

nonsense mutation

Answer 23

base substitution forms stop codon

protein synthesis stops before correct termination point

Question 24

frameshift

Answer 24

insertions and deletions

shift codon reading frame to change amino acid sequence

Question 25

inversions

Answer 25

reverse DNA base sequence of gene

Question 26

duplications

Answer 26

inserts additional copies of DNA sequence into genome

Question 27

translocation

Answer 27

DNA moves from 1 chromosome to another

Down’s syndrome