BIOL 1000 Lecture Notes - Lecture 24: Microtubule, S Phase, Mitosis
Document Summary
All cell types divide at different rates (e,g skin cells are always dividing, liber when needed, nerve cells never) Modulated by various factors including extracellular signalling molecules such as. It checks what the cell is doing hormones. Cell cycle stops at a checkpoint & only starts again if given the (cid:862)go(cid:863) signal. Things are checked at the (cid:862)checkpoint(cid:863)- favourable environmental conditions, everything that should have occurs has occurred, no components are damaged. Are materials for the next phase ready. If conditions are favourable & dna is not damaged the cell cycle continues. G1 checkpoint: damage to dna & other external factors are evaluated. If conditions are inadequate, the cell will not be allowed to continue to s phase of interphase. G2 checkpoint: ensures that all chromosomes have been replicated & that the replicated dna ins not damaged before cell enters mitosis.