Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Prokaryotes

67,948 views

Published on

For the IB Diploma Programme Biology Course.

Published in: Education, Technology

Prokaryotes

  1. 1. Prokaryotes Stephen Taylor i-Biology.net Image: Hospital-associated MRSA by NIAID on Flickr http://flic.kr/p/a4RLq5
  2. 2. Prokaryotes “Before nucleus:” evolutionary precursors to eukaryotes. Escherichia coli (E. coli) http://en.wikipedia.org/wiki/Escherichia_coli
  3. 3. Prokaryotic Cell Parts mesosome cell wall plasma membrane pili cytoplasm nucleoid ribosomes flagella Prokaryotic cell parts are not generally membrane-bound, so we don’t refer to them as organelles. Cell structures animation: http://www.wiley.com/legacy/college/boyer/0470003790/animations/cell_structure/cell_structure.swf
  4. 4. Prokaryotic Cell Parts mesosome cell wall: protective protein-based coating (Gram + / Gram -) plasma membrane: selectively permeable, controls entry & exit of materials to and from the cell. pili: attach to other bacteria for DNA transfer cytoplasm: contains enzymes for metabolic reactions nucleoid: closed-loop of bacterial DNA in a condensed area ribosomes: protein synthesis (transcription & translation) flagella: whiplash-like motion causes movement Cell structures animation: http://www.wiley.com/legacy/college/boyer/0470003790/animations/cell_structure/cell_structure.swf
  5. 5. Prokaryotic Cell Parts mesosomes These don’t really exist naturally as bacterial cell parts, and could be an example of a paradigm shift in thinking. They were observed in some electron micrographs and thought to be in-folds of membrane used for division, respiration or making cell walls… … turns out they are an artifact of the preparation method for some electron microscope images. http://en.wikipedia.org/wiki/Mesosome Cell structures animation: http://www.wiley.com/legacy/college/boyer/0470003790/animations/cell_structure/cell_structure.swf
  6. 6. Past-paper question: E. coli TEM image Identify these structures: I. II. III. IV. Calculate the magnification of the image. Image from IB Biology QuestionBank CDRom – get a copy here: https://store.ibo.org/biology
  7. 7. Past-paper question: E. coli TEM image Identify these structures: I. Plasma membrane II. Cell wall / pili III. Nucleoid IV. Cytoplasm / ribosomes Calculate the magnification of the image. 1. Measure the scale bar in mm. 2. Multiply x 1000 to convert to μm. That is the magnification. How long is the bacterium? Image from IB Biology QuestionBank CDRom – get a copy here: https://store.ibo.org/biology
  8. 8. PROKARYOTES E P R O D U C E through binary fission two-parts splitting
  9. 9. PROKARYOTES binary fission E through P R The closed-loop DNA of the O bacterium makes copies through semi-conservative DNA replication. D U New plasmids are pulled to opposing poles by the spindle fibres. C The bacterium divides in two. E
  10. 10. http://www.youtube.com/watch?v=gEwzDydciWc
  11. 11. How dirty is your phone? http://www.youtube.com/watch?v=4lmwbBzClAc
  12. 12. Prokaryotes divide by binary fission. Life cycle of E. coli from: http://en.wikipedia.org/wiki/Escherichia_coli
  13. 13. A man got sick from E. coli after eating old sausages. He’d contracted a porkaryote. Photo: Sausages by Paul Hickman on Flickr (CC) http://flic.kr/p/bzcFSn
  14. 14. For more resources & links. Please consider a donation to charity via Biology4Good. Click here for more information about Biology4Good charity donations. This is a Creative Commons presentation. It may be linked and embedded but not sold or re-hosted.

×