mitosis and meiosis

  • Created by: Sarah
  • Created on: 02-06-18 10:39
what is the chiasma?
where crossing over takes place
1 of 68
what are the stages of the cell cycle?
G1, G2 , Synthesis (DNA replcation), mitosis
2 of 68
what is interphase?
G1 + S + G2
3 of 68
How long can G1 be?
very long or permeant
4 of 68
how long does it take mammlain cells to divide if they're in a proliferative state?
around 24 hours
5 of 68
what cells do not divide?
differentiated cells
6 of 68
what are sister chromatids?
identical copies of the maternal and paternal homologues
7 of 68
what are the homologoues?
1 maternal and 1 paternal homologue
8 of 68
after DNA replication what have you got?
sister chromatids (copies)
9 of 68
stages of mitosis?
PMAT- prophase, metaphase, anaphase and telophase
10 of 68
what happens in telophase?
cytokinesis
11 of 68
what happens in prophase?
condensation of sister chromatids need to package the DNA to be able to pull the, apart
12 of 68
what happens in metaphase?
chromatids line up along the metaphase plate and are attached to the spindle. chromosomes attached to spindle by MT into kinetochore
13 of 68
what happens in anaphase?
segragation of sister chromatids
14 of 68
What 2 types of yeast are used to study cell cycle?
fission yeast- pombe and budding yeast- cerevisae
15 of 68
how do you study cell cycle with fission yeast?
they grow out and do cell cycle in 1D so can measure them
16 of 68
what are yeast good to study cell cycle with?
genetics
17 of 68
why can budding (cervesiae) yeast be used?
can measure the size of bud to see how far through cell cycle
18 of 68
advantages of yeast in cell cycle?
1) rapid division rate 2) never reach homeostasis always dividing 3) cell cycle genes highly conserved 4) grown as haploid or diploid
19 of 68
where were cdc (cell division cycle genes) named?
in yeast so when discovered in human still carried yeast name
20 of 68
why is it good to be able to grow yeast as haploid or diploid?
diploid can be heterozygous- 1 good and 1 bad copy of the gene grow up colony as diploid then make haploid to see effect of the gene
21 of 68
how else can you study cell cycle genes in yeast?
1) grow as diploid and turn haploid 2) temperature sensitive mutations
22 of 68
what is the principle behind temperature sensiitve mutations?
can grow up colony with permissive temp then change to restrictive temp will mutate gene and will all arrest at one stage of cell cycle
23 of 68
what are checkpoints needed for in the cell cycle?
tissue size + growth also very important in cancer
24 of 68
when is the start checkpoint?
endish of G1
25 of 68
what is the start checkpoint checking?
is env favourable
26 of 68
what is the next checkpoint after the start checkpoint?
G2/M checkpoint- between G2 and metaphase
27 of 68
what is the G2/M checkpoint for?
to check all DNA is rep? is env favourable
28 of 68
what is the metaphase to anaphase checkpoint for? what protein is involved here?
is all chr attached to the spindle? APC
29 of 68
what is APC?
Anaphase promoting complex- ubiquitin ligase
30 of 68
what is APC needed for?
to check all chrs are attached to the spindle
31 of 68
what does APC ubiquitinate?
M cyclin, S cyclin, Securrin
32 of 68
what does APC regulate?
E1 + E2 ubiquitination enzymes
33 of 68
what subunit is needed to activate APC?
cdc20 subunit
34 of 68
what is securin needed for?
securin is a protein that holds together sister chromatids when estroyed will allow anaphase to begin
35 of 68
what cyclins drop at Metaphase to anaphase checkpoint?
M cyclin + S cyclin- destroyed by APC
36 of 68
what is APCs function?
The APC/C's main function is to trigger the transition from metaphase to anaphase by tagging specific proteins for degradation. The three major targets for degradation by the APC/C are securin and S and M cyclins.
37 of 68
what are different inputs into cdks important for?
make sure you don't begin the next phase until everythings accomplished
38 of 68
what are gametes?
haploid
39 of 68
what needs to be packaged into each gamete?
only 1 homologue- either maternal or paternal
40 of 68
what part of meiosis is like mitosis?
meiosis 2- involves separating sister chromatids
41 of 68
what happens in meiosis 1?
lining up of sister chromatids, crossing over and separate homologues
42 of 68
what is separated in meiosis 1?
homologues
43 of 68
what is separated in meiosis 2?
sister chromatids
44 of 68
what activates cdks?
cyclins
45 of 68
what does wee1 kinase do?
inhibits cdks by adding an inhibitory phosphate
46 of 68
what does cdc25 phosphatase do?
removes inhibitory phosphate from cdk and activates it
47 of 68
what is expression of cyclins dependent on?
stage of cell cycle
48 of 68
what happens when cyclins activate cdks
cdks go around phosphorylating proteins needed for that stage of the cell cycle
49 of 68
what can bind to cdk to inactivate it?
p27
50 of 68
what happens in meiosis I?
duplication -> makes sister chroamtids - pair up in metaphase, crossing over + segragation of homologues
51 of 68
what are the cells by the end of meisois I?
haploid
52 of 68
what is the difference between meiosis II and mitosis?
both separating sister chromatids but meiosis cell is haploid whilst mitosis cell is diploid
53 of 68
when do homologues pair up?
meiosis I prophase
54 of 68
when homologues pair up how many copies of the chromosome do you have?
4 copies- replicated maternal and paternal chr
55 of 68
what is pairing of the homologues facilitated by?
synaptonemal complex
56 of 68
what is a bivalent? wgat is it needed for?
a pair of homologues chromosomes- hold maternal and paternal together allows crossing over to take place and formation of chiasma
57 of 68
what is chiasma?
where crossing over takes place
58 of 68
what 2 purposes does HR serve?
1) aligns chromosomes ready for anaphase + facilitates formation of synpatonmeal complex 2) allows for genetic recombination needed for genetic variation
59 of 68
what is non disjunction?
where you don't have the right chormosome number
60 of 68
what are gametes that arise from non disjunction called?
aneuploid- don't have the right ploidy
61 of 68
how much of mammalian sperm and eggs are aneuploid?
4% sperm 20% eggs
62 of 68
what does aneuploid gametes result in?
miscarriage or down syndrome
63 of 68
why do we do crossing over if it's risky
evolution huge advantage
64 of 68
what are xenopus used to study?
biochemical approach to cell cycle
65 of 68
advantage of xenopus as cell cycle model?
rapid division, lay lots of eggs, cell free mitosis, large size- can inject inhibitors and RNA
66 of 68
how do you do cell free mitosis?
take cytoplasm from eggs and sperm and ATP put in a test tube will start mitosis
67 of 68
how can cell free mitosis be manipulated?
can add antibodies follow proteins or take samples at different stages eg see if phosphorylated
68 of 68

Other cards in this set

Card 2

Front

what are the stages of the cell cycle?

Back

G1, G2 , Synthesis (DNA replcation), mitosis

Card 3

Front

what is interphase?

Back

Preview of the front of card 3

Card 4

Front

How long can G1 be?

Back

Preview of the front of card 4

Card 5

Front

how long does it take mammlain cells to divide if they're in a proliferative state?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all cell bio resources »