BIOL 2021 Chapter Notes - Chapter 1.1: Fas Ligand, Apoptosis, P53
2 Apr 2018
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Signal proteins between digits (fingers) in developing embryos (sculpting) Tadpoles use thyroid hormones in their tails as a signal for apoptosis. Most animal cells require survival signals to stay alive. Survival signals bind to receptors and inhibit apoptosis. Fig 15-4: different pathways of signals and different cells experience signals differently. Too much apoptosis can cause tissue damage: ex. heart attacks and strokes, initial damage isn"t that bad, but the way the body responds to that damage can make things worse. Too little apoptosis leads to excessive cell numbers: ex. too many lymphocytes in the immune system (autoimmune disease) Cancer cells have heritable properties: reproduce without normal constraints on growth and division, invade and colonize new territory. Cancer can be defined as a genetic disease that is caused by individual mutant: mutant cells out-compete their neighbours by evolving. Evolution requirements: population must have heritable variation, natural selection for individuals with an advantage (leaving more progeny)
