Protein control of cell division Flashcards
What does the cytoskeleton do
provides framework of mechanical support
-maintains shape
what is the cytoskeleton made up of
microtubules made of tubulin
Where do microtbules radiate from
MTOC/centrosome
What do microtubules do
control the movement of membrane bound organelles
control movement of chromosomes during mitosis and meiosis
what does cell division require
polymerisation and depolymerisation of tubulin
What do microtubules form
spindle fibres
What phases is the interphase made of
g1 - growth
s - DNA replicated
g2 - further growth
What is cytokineses
cytoplasm separates into 2 daughter cells
what happens during prophase
DNA condenses into chromosomes
spindle fibres extend from MTOC and attatch to centromere
What happens during the metaphase
chromosomes meet at the metaphase plate
What happens during anaphase
spindle fibres shorten by depolymerisation and chromatids are separated
WHat happens during the telophase
chromosomes decondense nad nuclear membranes form around them
-CYTOKINESIS
What do cyclins do
regulate cell cycle
activate cyclin dependant kinase so it can phosphorylate proteins to regulate the cycle
Where are the checkpoints of the cell cycle
g1 g2 M
WHat happens at the G1 checkpoint
retinoblastoma acts as a tumor supressor and inhibits the transcription of genes that code for DNA replication
What happens at the G2 checkpoint
ddetermines how successfully DNA has been replicated
assesses any damage
-p53 triggered
-stimulate repair
-arrest cycle
-apoptosis
What does the metaphase checkpoint do
controls the progression from metaphase to anaphase
progression halted util chromosomes are aligned correctly on metaphase plate
-ensures cell receives correct number of chromosomes
describe external death signals
bind to surface receptor protein
-protein cascade in cytoplasm
caspase activated
cell death/digestion by protease enzyme
describe internal death signals
activation of p53
caspases activated
cell death/digestion by protease enzymes
What triggers apoptosis
lack of growth factors
