Topic 6: Mutations

Question 1

Point mutation

Answer 1

affect single or small number of nucleotides

Question 2

Substitutions

Answer 2

transition or transversion, point mutation

Question 3

transition

Answer 3

purine to purine OR pyrimidine to pyrimidine

Question 4

transversion

Answer 4

purine to pyrimidine OR vis versa

Question 5

Indel

Answer 5

Insertion/deletion mutation (addition, deletion)

Question 6

frameshift

Answer 6

add or delete base pairs (may occur by replication slippage at poly dN)

Question 7

repeated sequences

Answer 7

may result in larger indel mutations
-cross over and loop is deleted
(centromere and telomere)

Question 8

interstitial

Answer 8

in the middle of the chromosome

Question 9

terminal

Answer 9

at the end of the chromosome

Question 10

intra-genic

Answer 10

within the gene, deletion

Question 11

intergenic

Answer 11

between 2 genes

Question 12

multigenic

Answer 12

more than one gene affected (deletion)

Question 13

duplications

Answer 13

extra material for mutation

Question 14

inversion

Answer 14

paracentric or pericentric
-creates difficulty in homologous pairing and therefore unbalanced products

Question 15

paracentric

Answer 15

away from the centromere

Question 16

pericentric

Answer 16

including the centromere

Question 17

anticipation

Answer 17

diseases where you see changes in severity from generation to generation

Question 18

Fragile X syndrom

Answer 18

mental development handicap, sex-linked on X chromosome, more common in males

Question 19

translocations

Answer 19

involves 2 different nonhomologous chromosomes, can be caused by double strand breaks
- reciprocal or unbalanced

Question 20

aneuploidy

Answer 20

change in chromosome number
caused by nondisjunction

Question 21

nondisjuction

Answer 21

impropoer separation of chromosomes during cell division

Question 22

monosomy

Answer 22

absense of one member of a chromosome pair

Question 23

euploidy

Answer 23

normal number of chromosomes

Question 24

polyploidy

Answer 24

multiple chromosome sets, triploid, tetraploid, octoploid (strawberries)

Question 25

mobile genetic elements

Answer 25

ie, plasmids DNA sequences orginating in viruses and integrated into genomes

Question 26

synongmous

Answer 26

no change in amino acid (but there IS a change in DNA), silent

Question 27

missense

Answer 27

conservative/nonconservative - one amino acid is substituted for another

Question 28

conservative missense

Answer 28

same biochemical properties as substituted amino acid

Question 29

nonconservative missense

Answer 29

different biochemical properties as substituted amino acid, more likely to change function of protein

Question 30

nonsense

Answer 30

change of amino acid to a stop codon

Question 31

null

Answer 31

no effect, silent mutation (of protein)

Question 32

leaky

Answer 32

partially functioning (of protein- only some is made or not very functional)

Question 33

neutral

Answer 33

change but not a large effect on protein function (location is important)

Question 34

morphological mutation effects

Answer 34

affect form (size, shape, number, colour, etc)

Question 35

lethal

Answer 35

recessive, de novo (if not inherited, dominant, "novel")

Question 36

conditional mutation

Answer 36

mutant phenotype only expressed in certain conditions (ie. temp)

Question 37

restrictive condition

Answer 37

see mutant phenotype

Question 38

permissive condition

Answer 38

see wild-type phenotype

Question 39

suppressor

Answer 39

second mutation compensates for primary mutation

Question 40

regulatory mutation

Answer 40

occurs outside of coding region (ie. promoter and splice sites)

Question 41

loss-of-function

Answer 41

hypomorph, null

Question 42

gain-of-function

Answer 42

hypermorph

Question 43

haplosufficient

Answer 43

only one allele is necessary for phenotype

Question 44

haploinsufficient

Answer 44

heterozygotes: one copy of "normal phenotype" is not enough (mutant allele is dominant)

Question 45

ethylmethane sulfonate (EMS)

Answer 45

alkylating agent- transitions adds ethyl group onto G which miss-pairs bases (CG to AT or GC to TA)

Question 46

deamination

Answer 46

base alteration, transitions

Question 47

UV light

Answer 47

photo products of adjacent pyrimidines (thymidine dimer), transitions -double stranded DNA breaks also

Question 48

2-aminopurine (2-AP)

Answer 48

adenine analog GC to AT or AT to GC- transitions

Question 49

5-bromouracil (5-BU)

Answer 49

thymidine analog GC to AT or AT to GC- transitions

Question 50

Aflatoxin B1 (AFB1)

Answer 50

bulky adducts cause apurinic sites GC to TA transversions - become unweilding, base may fall out

Question 51

Acridine orange

Answer 51

intercalating agent frameshifts

Question 52

intercalating agent

Answer 52

planar molecules, insert into DNA molecule and makes DNA longer

Question 53

Ethidium bromide

Answer 53

intercalating agent, used in lab as a dye for DNA - fluoresces under UV light

Question 54

pseudogene

Answer 54

non-functioning copy of a gene, caused by duplication

Question 55

transformation

Answer 55

the change of a normal cell into a cell that is immortal (HeLa cells) can divide forever

Question 56

tumor suppressor genes

Answer 56

"brakes", stop normal cell division - inactivating mutations cause cancer

Question 57

proto-oncogenes

Answer 57

"gas", promote cell division - activating mutations cause cancer

Question 58

apoptosis

Answer 58

programmed cell death