BIO315H5 Lecture Notes - Lecture 25: Apoptosis, Chromosome, Chromosomal Rearrangement
Document Summary
Regulation of cell size and number: cell number- cells proliferating, cell division, cell dying (apoptosis, cell mass is controlled by separate pathways. 3 aspects are triggered by extracellular signals: signaling molecules don"t necessarily serve one function can serve more. Ie tgf beta (module 1) in the context of tgf beta smad signalling. In the nucleus, it can turn on expression of immediate early genes: remember immediate early genes are the ones that do not require new protein synthesis in order for transcription to occur. If something goes wrong, cell division is going to be blocked. In late g1- at the g1/s transition or g2/m. Cdc25 phosphatase: remember m cdk activation requires cdc25 phosphatase to remove the inhibitory phosphates on the cdk. If you inactivate it, you don"t get m cdk activation. Immortalized cells that don"t undergo replicative cell senescence have lost this or they have acquired telomerase activity, such as cancer cells.
