Kandpal- Replication and Telomeres Flashcards Preview

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Flashcards in Kandpal- Replication and Telomeres Deck (44):
1

what is the difference in number of replication origins between bacteria and mamallian cells?

bacteria have a single origin of replication and mammalian cells have multiple origins of replication

2

which ploymerase is has primase activity?

alpha polymerase

3

which polymerase has repair activity?

beta polymerase

4

which polymerase is used for mitochondrial replication?

gamma polymerase

5

which polymersae is needed for nuclear replication?

delta polymerase and gamma polymerase

6

are okazaki fragments bigger in mammalian cells than they are in bacteria cells?

no. they are smaller (0.1-0.2 Kb) and bacteria are bigger (1.0-2.0 Kb)

7

what is RNaseH needed for?

to degrade the RNA part of the RNA-DNA hybrid

8

what is the shape of a bacteria (e.Coli) genome and the shape of a mammalian genome?

bacteria is circular and mammalian is linear

9

at the end of replication, what happens after the RNA primer is removed from the 5' end?

it is not filled up, because there is no polymerase availabe with 3'--> 5' activity

10

what eventually happens to the 5' end?

they will continue to shorten after each replication cycle which can lead to consequences like eventual coding loss

11

what do chromosome replication and stable propagation require?

origins of replication

12

what helps to attach chromosomes to the nuclear envelope?

telomeres

13

why is it important that telomeres help to seal the ends of chromosomes?

to avoid undesirable fusion an avoid aberrant recombination

14

what kind of repeats do telomeres have and how are they synthesized?

hexameric repeats that are synthesized by telomerase

15

what makes up a telomerase?

Ribonucleoprotein (protein+RNA)

16

what subunit of telomerase is responsible for reverse transcriptase activity?

Protein subunit

17

which subunit of the telomerase helps to serve as a template?

RNA (150 nucleotide long)

18

what does C-A strand degradation in telomeres lead too?

generation of G-tail

19

what is the proposed model that describes how telomeres protect chromosome ends?

G-quadruplex or G-Quartet Structure.
4 G bases on the same strand stack-up by base pairing

20

what type of cells in humans are known to have telomerase activity?

germ cells, isolated fibroblasts (mainly in elderly individuals)

21

telomeres are referred to as the mitotic clock. why?

because the shorter they become in length, the more likely replicative senescense or apoptosis will occur

22

how does telomerase activity relate to human cancer?

normal tissues will not have telomerase (except germ cell) but tumors have telomerase activity

23

what would a scientist target in order to intervene in antitumor activity?

telomerase activity and telomere structure

24

what is the function of the telomerase inhibitor GRN163L (oligonucleotide)?

it is a competitive inhibitor that binds to the active site of the enzyme (13-mer oligonucleotide)

25

what are the effects of the G-qudruplex stabilizing agent RHPS4 (G-quadruplex ligand)?

stabilizes G-quadruplex and prevents attachment of telomerase.

26

what is pentacylic acridinium methosulfate?

RHPS4 (G-quadruplex ligand)

27

what is considered to be an obligatory intracellular parasite?

virus (completely dependent on host)

28

what is the name for an inert virus and what is the outer protective layer called?

virion. the nucleic acid is wrapped in a capsid

29

can viruses have envelopes?

technically yes, if they acquire them from the host cell membrane

30

is virus DNA single or double stranded?

both

31

is virus RNA single of double stranded?

both

32

how are viral nucleic acids replicated?

only replicated in host cells using host cell machinery

33

how does a viral genome replicate?

requires reverse transcriptase so that RNA can be converted to DNA for replication

34

why do viruses require integrase enzyme?

in order for cDNA to be integrated into the host genome

35

how does reverse transcription work during HIV replication?

utilizes lysyl tRNA as a template

36

what would be a target to inhibit HIV replication?

replication integrase protease

37

what is targeted to prevent HIV infection?

fusion, reverse transcriptase, pretease and integrase

38

what is a common nucleotide analogue drug that is used for treatment of HIV?

zidovudine (ZDV, AZT) which is an analouge of deoxythymidine

39

how does zidovudine work?

prevents DNA chain elongation by reverse transcriptase (absence of 3' OH)

40

antibiotics use inhibitors of what enzyme to prevent DNA replication?

inhibitors of bacterial gyrase

41

chemotherapy uses inhibitors of what enzyme to prevent DNA replication?

inhibitor of human topoisomerases

42

what 4 things would you want to inhibit the synthesis of in order to limit the supply of substrates?

dATP, dCTP, dGTP, dTTP

43

what is the role of 5-Fluorouracil in cancer chemotherapy?

inhibits DNA synthesis by inhibiting thymidylate synthase (an enzyme for TMP synthesis)

44

what drug is enzymatically converted to fluorouracil in the body if it is orally-adminstered?

capecitabine (Xeloda)