the cell cycle Flashcards
prophase
chromosomes condense, spindles form and nuclear envelope breaks down
metaphase
chromosomes align
anaphase
chromosomes separate and pulled towards the spindle poles
telophase
formation of the nuclear envelope, chromosomes decondense
cytokinesis
a contractile ring seperates the daughter cells
what does cell viability and integrity depend on
accurate duplication and segregation
name 4 pathways a cell can take
1) grow and divide which leads to proliferation and increase in cells
2) differentiation cell levels remain the same
3) death leads to apoptosis and decrease in cell levels
4) rest which leads to quiescence and cell levels remain the same
what is cell synchronisation
a method to study mammalian cells by using reversible inhibitors
what is colcemid
method to study cell by binding microtubules which inhibits M phase
what is thymidine
it inhibits DNA replication in the S phase
what is hydroxyurea
inhibits DNA replication in S phase
how can DNA synthesis be marked
by the use of bromodeoxyuridine and anti-BrdU antibodies
how can you study the DNA content
using flow cytometry
when measuring the cell cycle what fluorescence dye do you use that binds to the DNA
propidium iodide labelling
yeast cells grow normally at low temperatures what happens when they are in very high temperatures
they can’t continue normally in the cycle and are arrested and pile up
what comparisons were made between mouse and yeast CDC2 protein
62% identical
the protein was structurally and functionally conserved
what factors are involved in the G2/M phase transition
CDK1 in humans- protein kinase
CDC2 in yeast
cyclin B
Cdc25c -phosphatase
Wee1-protein kinase
CAK-protein kinase
what happens to protein levels in the G2/M phase
1) cdc2 or CDK1 proteins stay the same
2) cyclin B levels increase
3) the CDK1-cylin B complex activity increases
what does Wee1 phosphorylate
Y15 which leads to no ATP binding and an inactive CDK1
cyclin B must also be bound
what does CAK do
by phosphorylating T161 it activates CDK1 and allows substrate binding
cyclin B must also be bound
what happens to cyclin B in the G1 and S phase
cyclin B is degraded there is no phosphorylation of CDK1
how is cyclin B degraded
it is degraded by anaphase promoting complex. APC activated when chromosomes attach to spindle and align.
APC has ubiquitin ligase activity
also degrades securin
what happens to CDK1 phosphorylation in G2 phase
wee1 inactivates the CDK1 cyclin B complex. Cdc25c gets rid off the phosphorylation.
what changes occur in the levels during the G2/M phase
1) CAK activity remains same
2) wee1 activity decreases when entering M phase
3) cdc25 activity increases as entering M phase
