questions about mitochondria

Iuval Clejan clejan at mindspring.com
Thu Sep 7 22:07:59 EST 2000

Thanks for all the replies and pointers to the Alberts' book.

>From Alberts': "In most vertebrates oocyte maturation is arrested at metaphase
of meiosis II and the secondary oocyte completes meiosis II only after
Does this mean that the oocyte divides into an egg with a sperm and a polar
body, after the sperm enters it? Metaphase is before actual division, so this
seems to be the case. But it doesn't sound right.

Refined hypothesis A: During telophase I and/or II of meiosis, "good"
mitochondria stay in the oocyte and "bad" mitochondria end up in the polar
body. This mechanism is responsible for resetting of the ageing clock in most
vertebrates. Any ideas on what it would take to test this hypothesis?

Hypothesis B: "Bad" mitochondria only occur at cellular senescence, or in non
dividing cells. Since eggs don't experience cellular senescence, there is no
need to reset the clock. How to test this one?


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