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1. 2006-2007 Cellular Respiration Stage 4: Electron Transport Chain
2. Cellular respiration
3. 2006-2007
4. ATP accounting so far� Glycolysis ? 2 ATP
Kreb�s cycle ? 2 ATP
Life takes a lot of energy to run, need to extract more energy than 4 ATP!
5. There is a better way! Electron Transport Chain
series of molecules built into inner mitochondrial membrane
along cristae
transport proteins & enzymes
transport of electrons down ETC linked to pumping of H+ to create H+ gradient
yields ~34 ATP from 1 glucose!
only in presence of O2 (aerobic respiration)
6. Mitochondria Double membrane
outer membrane
inner membrane
highly folded cristae
enzymes & transport proteins
intermembrane space
fluid-filled space between membranes
7. Electron Transport Chain
8. Remember the Electron Carriers?
9. Electron Transport Chain
10. Stripping H from Electron Carriers NADH passes electrons to ETC
H cleaved off NADH & FADH2
electrons stripped from H atoms ? H+ (protons)
electrons passed from one electron carrier to next in mitochondrial membrane (ETC)
transport proteins in membrane pump H+ (protons) across inner membrane to intermembrane space Oxidation refers to the loss of electrons to any electron acceptor, not just to oxygen.
Uses exergonic flow of electrons through ETC to pump H+ across membrane.Oxidation refers to the loss of electrons to any electron acceptor, not just to oxygen.
Uses exergonic flow of electrons through ETC to pump H+ across membrane.
11. Pumping H+ across membrane � what is energy to fuel that?
Can�t be ATP!that would cost you what you want to make!
Its like cutting off your leg to buy a new pair of shoes. :-(
Flow of electrons powers pumping of H+
O2 is 2 oxygen atoms both looking for electronsPumping H+ across membrane � what is energy to fuel that?
Can�t be ATP!that would cost you what you want to make!
Its like cutting off your leg to buy a new pair of shoes. :-(
Flow of electrons powers pumping of H+
O2 is 2 oxygen atoms both looking for electrons
12. Electrons flow downhill Electrons move in steps from carrier to carrier downhill to O2
each carrier more electronegative
controlled oxidation
controlled release of energy Electrons move from molecule to molecule until they combine with O & H ions to form H2O
It�s like pumping water behind a dam -- if released, it can do work
Electrons move from molecule to molecule until they combine with O & H ions to form H2O
It�s like pumping water behind a dam -- if released, it can do work
13. We did it! Set up a H+ gradient
Allow the protons to flow through ATP synthase
Synthesizes ATP
ADP + Pi ? ATP
14. The diffusion of ions across a membrane
build up of proton gradient just so H+ could flow through ATP synthase enzyme to build ATP Chemiosmosis Chemiosmosis is the diffusion of ions across a membrane. More specifically, it relates to the generation of ATP by the movement of hydrogen ions across a membrane.
Hydrogen ions (protons) will diffuse from an area of high proton concentration to an area of lower proton concentration. Peter Mitchell proposed that an electrochemical concentration gradient of protons across a membrane could be harnessed to make ATP. He likened this process to osmosis, the diffusion of water across a membrane, which is why it is called chemiosmosis.Chemiosmosis is the diffusion of ions across a membrane. More specifically, it relates to the generation of ATP by the movement of hydrogen ions across a membrane.
Hydrogen ions (protons) will diffuse from an area of high proton concentration to an area of lower proton concentration. Peter Mitchell proposed that an electrochemical concentration gradient of protons across a membrane could be harnessed to make ATP. He likened this process to osmosis, the diffusion of water across a membrane, which is why it is called chemiosmosis.
15. Peter Mitchell Proposed chemiosmotic hypothesis
revolutionary idea at the time
17. Cellular respiration
18. Summary of cellular respiration Where did the glucose come from?
Where did the O2 come from?
Where did the CO2 come from?
Where did the CO2 go?
Where did the H2O come from?
Where did the ATP come from?
What else is produced that is not listed in this equation?
Why do we breathe? Where did the glucose come from?
from food eaten
Where did the O2 come from?
breathed in
Where did the CO2 come from?
oxidized carbons cleaved off of the sugars
Where did the CO2 go?
exhaled
Where did the H2O come from?
from O2 after it accepts electrons in ETC
Where did the ATP come from?
mostly from ETC
What else is produced that is not listed in this equation?
NAD, FAD, heat!Where did the glucose come from?
from food eaten
Where did the O2 come from?
breathed in
Where did the CO2 come from?
oxidized carbons cleaved off of the sugars
Where did the CO2 go?
exhaled
Where did the H2O come from?
from O2 after it accepts electrons in ETC
Where did the ATP come from?
mostly from ETC
What else is produced that is not listed in this equation?
NAD, FAD, heat!
19. Taking it beyond� What is the final electron acceptor in Electron Transport Chain? What if you have a chemical that punches holes in the inner mitochondrial membrane?What if you have a chemical that punches holes in the inner mitochondrial membrane?
20. 2006-2007