BIO 1140 Lecture Notes - Lecture 2: Cell Cycle Checkpoint, Apoptosome, Apaf1
16 Feb 2016
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The size of organ/organisms depends on the total cell mass-cell number must be controlled. Cell death triggers: chemical messengers, stress, cell cycle checkpoint -depends on how the cell dies. Much of the initial work on apoptosis was conducted using a nematode c. elegans(tiny round worm). Two cell-death mechanisms and the role of mitochondria and calcium in each. Because during development the same 131 cells apoptose every time. *c. elegans genes have human homologs: ced4 is a homolog to human apaf1 ced3 to caspase 3 ced9 to bcl2. The cristae are rearranged to facilitate release and a permeability pore is made. The calpain-cathepsin pathway: calpain is a calcium-dependant protease; it degrades the lysosome and leads to cathepsin proteases to be released; they digest all cellular content. There is a change in osmotic pressure which changes selective permeability of the plasma membrane; hypotonic. The transport systems and membrane system shuts off, loss of atpase activity, electrochemical gradient, energy depletion.
