Cell Energetics 2

Out line Cellular respiration Photosynthesis Kreb’s cycle Electron transport chain Photosynthesis Photosystem II Photosystem I

Recall from the last class What happen and where do energy producing processes take place?

What happen to the first cell on Earth regarding O2 respiration? Answer ? Fermentation follow by anaerobic respiration and aerobic respiration and photosynethesis Is there any oxygen on Earth at the beginning? How microorganism survive?

Energy producing cell structure http://0.tqn.com/d/biology/1/0/W/X/mitochondrion.png

Structure of Mitochondria

Membrane based energy production What is the significance of internal structure of mitochondria for ATP production? Membrane based energy production

http://www. eschooltoday http://www.eschooltoday.com/energy/renewable-energy/images/hydro-electric-dam.jpg

The linkage of electron transport, proton pumping, and ATP synthesis was called the chemiosmotic hypothesis or chemiosmosis coupling

Specifically, where does this proton gradient occur inside mitochondria?

Mitochondrial membrane Which membrane allow and not allow biomolecule to pass through? Why does the inner membrane of mitochondria fold? Where do electron-transport chain, protein pump and ATP synthase occur?

What happen inside mitochondria? Convert pyruvate to acetyle Co A Citric acid cycle or Kreb’s cycle Produce 2 CO2 No O2 involve in this process Generate ATP, high energy electrons carried by the activated carrier molecules 3 NADH and 1 FADH2

Citric acid cycle (Kreb’s cycle)

Where does the Kreb’s cycle take place? Matrix inside mitochondria

Electron transport chains Over 40 proteins Embeded in inner mitochondrial membrane Can be divided into 3 large respiratory enzymes (1) the NADH dehydrogenase complex (2) the cytochrome b-c1 complex (3) the cytochrome oxidase complex

Why does this process star from NADH and finish at O2 as H2O?

Proton motive force both charge and H+ gradient

ATP Synthase the same enzyme occurs in the mito-chondria of animal cells, the chloroplasts of plants and algae, and in the plasma membrane of bacteria

Proton motive force drive the transport of other chemicals into and out of mitochondria

How electron move from one to another complex Carriers move along lipid bilayer

The linkage of electron transport, proton pumping, and ATP synthesis was called the chemiosmotic hypothesis or chemiosmosis coupling

Cytochrome family Cytochrome family: Cytochrome c and cytochrome oxidase complex contain Fe in oxidized form. It is reduced to transfer electron to the better electron accepters (cytochrome oxydase complex or oxygen) Cytochrome oxidase complex prevent O2- (very reactive) to attack cell by tightly bound molecule of O2 until it pick up 4 electron and release as water

Chloroplast

Carbon fixation

Carbon fixation Glucose synthesis

Recommended Books Lodish, H., Berk, A., Matsudaira, P., Kaiser, C.A., Krieger, M., Scott, M.P., Zipursky, L., Darnell, J. 2004. Molecular Cell Biology, 5th ed, W.H. Freeman, Alberts, B., Bray, D., Hopkin, K., Johnson, A., Lewis, J., Raff, M., Roberts, K. & Walter, P. 2010. Essential cell biology, 3rd ed, Garland Science, New York.