Cell cycle control Flashcards
name 4 stages in cell cycle
G1, S, G2, mitosis
which stages make up interphase?
C1, S, G2
what is G0?
Gzero phase- resting phase - in a non-dividing state
what are G1 and G2 phases?
G1- duplication/cell growth of organelles and cellular componenets. G2 is double checking and growth
(no chormosome duplication)
what happens in S phase?
DNA replication + chromosome duplication
what happens in M phase?
mitosis - nuclear and chromosomal division (cytokineses)
how is cell cycle checked?
checkpoints (before end of G1 and G2) - negative signals
unattached chromosomes send negative signals
why is negative feedback used and not positive?
intensity between positive feed back would be difficult to distinguish whether chromosome attached or unattached
what is cell cycle controlled by?
cyclically active kinases
what happens to cyclins and CDK levels during cell cycles?
cyclins are synthesized then degraded
CDK levels remain relatively constant
what triggers entry into meiosis?
M-CDK
what controls metaphase-anaphase transition?
proteolysis
what can unchecked division lead to?
cell death, hyperplasia, cancer
