Lecture 35 notes W11

Lecture 35 notes W11 - Lecture 35 Notes I Bacteria and...

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Lecture 35 (4-11-11) Notes I. Bacteria and Archaea A. Probably tens of millions of species on this planet (wherever you find water, you’ll find microbial life, even in extreme environments) B. More prokaryotic cells associated with a human than eukaryotic cells C. Sequence of rRNA suggested that life can be grouped into three domains, Bacteria, Archaea and Eukarya. 1. The first branch separated bacteria and the archaea/eukarya common ancestor. D. This idea was once controversial. 1. Bacteria and Archaea are both unicellular. 2. Neither have nuclear envelopes and both have circular chromosomal DNA. E. Biochemical comparison of Bacteria and Archaea favor a common link between Archaea and Eukarya 1. Bacteria don’t have histones; archaea and eukarya do 2. RNA polymerase in archaea is more complex than bacteria, similar to eukarya 3. Bacteria use formylmethionine to initiate translation; archaea and eukarya use methionine. II. More reasons to find microbes interesting A. Many bacteria and archaea live in environments that scientists once thought were sterile. 1. If you put seawater on bacterial plates, nothing grows. 2. If you use PCR primers corresponding to the most conserved regions of the major rRNA gene, you find that seawater is full of different bacterial and archaeal species. 3. Challenge now to grow these microbes in the lab to study them in more detail (not always easy) III. Most human mortality in the world is caused by bacteria. A. Antibiotics and improved public health have been the major public health triumph of the
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This note was uploaded on 02/13/2012 for the course BIO 172 taught by Professor Clark during the Winter '08 term at University of Michigan.

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Lecture 35 notes W11 - Lecture 35 Notes I Bacteria and...

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