LIFESCI 7B Chapter N/A: LIFESCI 7B Chapter N/: LIFESCI 7B Chapter N/: LIFESCI 7B Chapter : LS7B Week 7 Monday reading
15 Feb 2019
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Document Summary
Mitochondria are also like chloroplasts in having a small genome. Indeed, the mitochondrial genome is dramatically reduced compared to the ancestral proteobacterial genome, in most eukaryotes containing only a handful of functioning genes. Human mitochondria, for example, code for just 13 proteins and 24 rnas. Biologists earlier hypothesized that these eukaryotes evolved before the endosymbiotic event that established mitochondria in cells having a nucleus, but that proposal turns out to be wrong. In fact, many eukaryotes that lack mitochondria contain small organelles called hydrogenosomes that generate atp by anaerobic processes (fig. These organelles have little or no dna, but genes of mitochondrial origin in the cells" nuclei code for proteins that function in the hydrogenosome. As discussed, many nuclear genes originated with the mitochondria and chloroplasts acquired from specific bacteria. However, genes from other groups of bacteria also reside in the eukaryotic nucleus, recording multiple episodes of horizontal gene transfer through evolutionary history.
