Tekitada kunstlikult telomeraasi sisseviimisel rakku. Rakuliin sageli aneupolidne- kromosoomide arv normaalsest erinev (tavaliselt suurem). Eri rakutüübid transformeeruvad eri sagedusega, suured liikidevahelised erinevused. 5. Miks rakud vajavad kasvamiseks seerumit? Et rakud end hästi tunneksid. Seerum-keskkond + mitogeenid=kasvufaktorid ja muud proliferisatsiooniks vajalikud substansid. Enamasti kasutatakse veise loote seerumit (FBS (ka FCS) foetal bovine serum) kontsentratsiooniga 10%. Seerum on hüübinud vere vedel osa. Seerumi koostis pole defineeritud, ta sisaldab albumiine, kasvufaktoreid ja teisi valke, vitamiine, rasvhappeid, lipiide jm; seerum suurendab ka söötme puhverdamisvõimet. 6. Miks peab rakkude külmutamisel lisama DMSO-d? Dimetüülsulfoksiid. Kaitseb rakke külmutamise ajal. Soojas on rakkudele kahjulik. 7. Mis on Bürkeri kamber? Rakkude loendamise kaadervärk 8
pigment) and some do not (making black pigment). This can only happen in cats with two X chromosomes. Male cats only inherit one X chromosome so this is active in all skin cells as there is nothing equivalent on the Y chromosome which could "switch off" the O gene. There are two main theories regarding brindled torties and patched torties. One (the "early/late deactivation theory") suggests that the time at which X chromosome deactivation occurs during foetal growth determines whether the cat has well defined patches or is brindled with intermixed black and orange hairs. Skin cells multiply during growth and spread out across the skin; as the embryo grows the skin cells multiply. If deactivation occurs early on each pigment cell has room to multiply into, a "red" cell will multiply into more red cells while a "black" cell will give rise to patches of black. If it occurs later, the patches are
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