mitochondrial inheritance/reproduction

[km1865]

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According to this website http://www.cytochemistry.net/cell-biology/mitochondria_lifecycle.htm , the sperm contains only about 100 mitochondria at the base of its tail compared to 100,000 in the oocyte.. that sort of goes against my logic since I thought the sperm needed more mitochondria because it is the more motile of the two gametes.. ??

Also, I know mitochondrial replication is completely random (with respect to the cell cycle of the cell containing the mitochondria) but how does mitochondrial translation work then? is it the mitochondria's own mRNA, and tRNA used by the mitchondria's OWN ribosomes.. or does mitchondrial mRNA get exported out of the mitochondria for translation by the cell's ribosome?

I really appreciate all the help! Thanks

 

[LeonVCU]

Don't worry about knowing details like this. Studying for the MCAT is not the time for that. The passage will give you all the picky details that you need to know. Instead focus on improving your passage comprehension and memorizing IMPORTANT details.

 

[Isoprop]

According to this website http://www.cytochemistry.net/cell-biology/mitochondria_lifecycle.htm , the sperm contains only about 100 mitochondria at the base of its tail compared to 100,000 in the oocyte.. that sort of goes against my logic since I thought the sperm needed more mitochondria because it is the more motile of the two gametes.. ??

That's interesting, I did not know that. My guess would be that oocyte once fertilized will need to undergo rapid succession of cell division. So it would be practical to have more copies of its organelles than normal.

Also, I know mitochondrial replication is completely random (with respect to the cell cycle of the cell containing the mitochondria) but how does mitochondrial translation work then? is it the mitochondria's own mRNA, and tRNA used by the mitchondria's OWN ribosomes.. or does mitchondrial mRNA get exported out of the mitochondria for translation by the cell's ribosome?

I really appreciate all the help! Thanks

Most mitochondrial proteins are transcribed from mitochondrial DNA. The mitochondria has its own ribosomes to translate those genes into proteins. Some mitochondrial proteins come from the nuclear genome that is transported into the mitochondria.

 

[neurodoc]

.. that sort of goes against my logic since I thought the sperm needed more mitochondria because it is the more motile of the two gametes.. ??

I really appreciate all the help! Thanks

Motility is almost all that the spermatozoa need their mitochondria for; and their mitochondrial DNA doesn't get incorporatedinto the zygote. The oocyte's mitochondria take care of the energy requirements of the developing zygote. That's why an organism's mitochondrial DNA follows a maternal lineage.

 

[whiteshadodw]

the sperm travels quite far to get to the egg, but they have plenty of nutrients to get them through the journey (think about the supporting fluids in ejaculate).