BIOL 355- Midterm Exam Guide - Comprehensive Notes for the exam ( 79 pages long!)
12 Oct 2017
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Hayflick limit: cells (cid:449)ill di(cid:448)ide a(cid:374)d reprodu(cid:272)e o(cid:374)ly a li(cid:373)ited (cid:374)u(cid:373)(cid:271)er of ti(cid:373)es (cid:862)(cid:272)ell (cid:272)lo(cid:272)k(cid:863, number is genetically programmed. Could the biological clock be within each cell. Aging must occur from inside the cell. Cells grown in vitro have demonstrated they have a fixed number of times they can divide. Defined as the number of times cells in culture can replicated before they stop dividing and die. One serial passage or population doubling of cells. Population doubling is literally going from one culture plate in which the cells are completely covering the bottom to 2 dishes, then 4 then 8 then 16. That is why is is called doubling. It is a doubling of the cultures and not the cells themselves. Cells from fetal tissue are capable of about 50 population doublings then lose ability to divide further in vitro.
