Mutations and DNA replication/repair Flashcards Preview

biochem 2 > Mutations and DNA replication/repair > Flashcards

Flashcards in Mutations and DNA replication/repair Deck (44):
1

how does depurination happen

bone between base and deozyribose spontaneously hydrolyzes

2

what is the most common deamination

spontaneous conversion of cytosine to uracil

3

how do you get pyrimidine dimers

UV light dimnerizes adjacent thymine bases

4

somatic muation

affects only the cell where the mutation happens

5

what happens if you have somatic muation early in embryogenesis

mosaicism

6

germline mutation

mutations gets passed to offspring

7

gene mutation

variation in nucleotide seque3nces

8

genomic mucations

surplus o rloss of chromosomes

9

chromosomal mutaitons

rearrangements, deletions, or duplications o fchromosomal regions

10

mutations involving chromatin

changes in methylation of DNA

11

what is the most common type of mutaiton

gene mutation

12

what are the 3 mechanisms that cause small insertions and deletions

incorrect recomination
strange slippage
intercalating agents

13

what happens iwth incorrect recomination

unequal crossover

14

where is incorrect recombination more likely to happen

loci that have repetitive DNA

15

where is strand slippage during replication likely to happen

areas of repetitive sequence

16

intercalating agents

chemical mutagens that fuck up DNA

17

what is a source of chromosomal and genome mutation

meiosis

18

prophase I

chromosomes condense and become visible

19

synaptonemal complex

holds together homologous chromosomes

20

chiasmata

sites of crossovers

21

metaphase

chromsomes are positioned at the equator

22

anaphase

chromsomes are serparted, pulled to opp. poles

23

process of pulling the chromsomes apart and to opposite ends of the cell

disjunction

24

nondisjunction

incomplete separation of chromosomes in anaphase

25

the frequency of nondisjunction increases with waht

maternal age

26

how does gene mapping work

use frequency of recombiantion between genes on teh same chromosome as an indicator of their proxiximity

27

3' --> 5' exonuclease activity of DNA polymerase delta

responsible for bulk of DNA synthsis during replication process

28

what happens if an incorrect nuclteotide is found by the exonuclase

it hydrolyzes the new phosphodiester bond adn the polyermase tries again for correct base pairing

29

what is HNPCC caused by

defects in mismatch repair system

30

DNA glycosylases

recognize specific types of altered base in DNA and catalyze their hydrolytic removal

31

nucleotide excision repair

repairs damage caused by agents that result in large changes in structure of DNA

32

waht casues xeroderma pigmentosum

mutation that abolism or impair function of nucletoide excision repair

33

symptoms of xeroderma pigmentosum

extreme sensitivity of skin to sunlight

34

nonhomoglous end joining

you just connect the breaks without adding back what was lost

35

homologous end joinging

us the recombination processes to repair broken DNA, no loss of information

36

how is cytarabine different from cytidine

contains arabinosine instead of ribose

37

what do you treat with cytarabine

acute leukemias

38

how does cytarbine work

turns into cytarabine triphosphate inside cells. competes with deoxyribonucleotides for binding to DNA polymerase, blocking DNA replication

39

what do you treat with cyclophosphamide

hodgkin's lymphoma

40

how does cyclophosphamide work

acts as alkylating agents, does damage to DNA

41

what is doxorubicin

anthracycline antibotic

42

how does doxorubicin work

forms complex with DNA and toposimoerase II

43

how does toposiiomerase II work

passing 1 double stranged DNA seg throough a double stranged break in another double stranded DNA segment

44

what happens after doxorubicins binds to toposiomerase II

double stranded breaks accumulate, lead to apoptosis