Lecture 3/12

Question 1

where will one find a protein that affects the protein activity, and is that a quantity or quality issue?

Answer 1

they MUST be inside the protein coding region; quality issue

Question 2

what are examples of mutations that can affect protein quality

Answer 2

nonsense, missense, frameshift, deletions

Question 3

where would you find mutations that affect the protein levels and is this a quality or quantity issue?

Answer 3

outside of the protein coding region; quantity issue

Question 4

what kinds of mutations can be found outside of the protein coding region?

Answer 4

point, deletion, substitution

Question 5

what kinds of mutations can not be found outside of the protein coding region?

Answer 5

nonsense, missense, frameshift

Question 6

what does it mean to be a hypermorphic mutation

Answer 6

it is a gain of function mutation that either makes more protein of a more efficient protein

Question 7

what kind of mutation can be a hypermorphic mutation?

Answer 7

any

Question 8

would a hypermorphic be found inside or outside the protein coding region? hypomorphic?

Answer 8

either can be found inside or outside the protein coding region

Question 9

what is considered to be the regulatory region?

Answer 9

5’ and 3’ UTR, outside of the protein coding region

Question 10

where is the promoter in relation to the protein coding region?

Answer 10

it is upstream of the initiator codon

Question 11

where is the promoter in relation to the regulatory region?

Answer 11

it is in the regulatory region

Question 12

what happens in a missense mutation?

Answer 12

one amino acid is replaced for another

Question 13

if there is a mutation between the promoter and the AUG, what region is that considered?

Answer 13

the 5’ UTR

Question 14

what does a forward mutation do?

Answer 14

changes WT allele to a different allele

Question 15

what does a reverse mutation/reversion do?

Answer 15

changes a mutant allele back to WT

Question 16

what does it mean to be an intragenic suppressor?

Answer 16

a second mutation in the same gene that reverts the effects of a mutation back to WT

Question 17

which rate is usually higher: forward mutation or reversion?

Answer 17

forward mutation

Question 18

what is a compensatory mutation?

Answer 18

restore or improve the effects of another mutation, often back to WT

Question 19

what is the calculation for determining spontaneous rates of mutation?

Answer 19

how many you see (# of mutations) divided by # of gametes tested (haploid)

Question 20

is spontaneous mutation rate calculated with diploid genome or haploid?

Answer 20

haploid

Question 21

what affects mutation rates?

Answer 21

differences in gene size and susceptibility to various mutagenic mechanisms (ie. if it’s in a hotspot for mutation)

Question 22

if a gene is bigger, is it more or less likely to mutate?

Answer 22

more likely

Question 23

is mutation rate in gamete-producing euks higher or lower than proks? why?

Answer 23

higher bc euk genome is bigger and there are more cell divisions bt zygote formation and meiosis in germ cells

Question 24

who tolerates mutations better, diploid or haploid organisms?

Answer 24

diploid bc generally mutations are recessive and you could still have WT function from one allele

Question 25

are bacteria diploid or haploid?

Answer 25

haploid

Question 26

what are the two hypotheses for why bacteria can be resistant to antibiotics? which is correct

Answer 26

they are exposed and therefore mutate in response, or they already have the mutations; the second hypothesis is correct

Question 27

what did the penicillin/bacteria experiment show? how?

Answer 27

that bacterial resistance is the result of preexisting mutations -- we can see this because of 3 triplicate plates where bacteria grow on a medium with penicillin and the bacteria that survive are always in the same spots. if the bacteria grew resistant as a result of exposure, the bacteria would grow randomly on the plate

Question 28

how do antibiotics work?

Answer 28

they disrupt a pore used for transport

Question 29

once mutations in bacteria (to make them resistant) occur, are those mutations stable or unstable?

Answer 29

they usually remain stable

Question 30

are mutations that occur in replication rare or common?

Answer 30

rare

Question 31

what do our bodies make in naturally occurring mutations?

Answer 31

free radicals (super oxide O2-) and hydrogen peroxide H2O2

Question 32

what cellular processes make free radicals and hydrogen peroxide?

Answer 32

oxidative phosphorylation, NADPH oxidase, and 5-lipoxgenase

Question 33

what are two enzymes that get rid of the free radicals and hydrogen peroxide

Answer 33

superoxide dismutase (ROS = reactive oxygen species) and catalase

Question 34

what can a superoxide do to an individual base?

Answer 34

it oxidizes it, causing oxidative damage and the potential to mispair after replication (the other strand would be fine)

Question 35

what kind of mutation occurs from an ROS?

Answer 35

point mutation

Question 36

what is a depurination?

Answer 36

removal of a purine (either A or G) by heat or acid and that apurinic site will randomly pair with another nucleotide

Question 37

which happens more often, depurination (A and G) or depyrimidination (C and T)?

Answer 37

depurination

Question 38

what happens in deamination of C?

Answer 38

the amino group is ripped off of C and replaced by an oxygen, making the look like a U, so it will pair with an A

Question 39

what kind of mutation is caused by deamination of C?

Answer 39

point mutation

Question 40

What do X-rays do to DNA?

Answer 40

they break the sugar-phosphate backbone, causing a double-stranded break

Question 41

what happens to the double stranded break from X-rays?

Answer 41

the strands are ligated back together, causing a deletion

Question 42

what does UV light cause to happen in DNA?

Answer 42

adjacent Ts will create a thymine dimer, causing abnormal pairing

Question 43

what happens at high intensity UV?

Answer 43

double-stranded breaks

Question 44

what does a hydroxylating agent do?

Answer 44

adds an OH group

Question 45

what do hydroxylating agents do to DNA

Answer 45

if they add an OH group to a C, it will make it look like a T and then it will pair with an A

Question 46

what do alkylating agents do?

Answer 46

add an ethyl or methyl group

Question 47

what happens when you add an ethyl group to a G?

Answer 47

If you add an ethyl group to a G, it looks like an A and will pair with a T

Question 48

what are transposable elements?

Answer 48

elements that move around the genome; they can jump into a gene and disrupt its function

Question 49

what are the two mechanisms of transposon movement?

Answer 49

Duplicates itself, excises and inserts itself elsewhere OR the transposon excises itself and randomly goes to another area

Question 50

there are repeats of CGG at the end of the FMR1 gene, what does that cause to happen?

Answer 50

there's a lot of slippage, causing it to keep getting replicated. you can end up with a damaging (fragile X) or non-damaging number of copies, it can also get twisted into a loop out

Question 51

what shape represents women in a pedigree?

Answer 51

circle

Question 52

what shape represents men in a pedigree?

Answer 52

squares

Question 53

what did muller find about drosophila in terms of x ray mutation

Answer 53

X rays can cause mutations, if F1 female has X-ray induced mutation, only males that survived had bar eyes