Biochemistry: Synthesis of ATP in the Mitochondria
Terms
undefined, object
copy deck
-
1. Describe the shuttle process where electrons from NADH is transferred into the mitochondrial matrix, but not directly with the NADH itself.
2. What is the name of the shuttle system?
3. What is the name of the electron acceptor -
Glycerophosphate shuttle... E-FAD -
IN the Glycerophosphate shuttle (n converting dihyroxyacetone phophate to glycerol-3-phosphate) is this rxn thermodynamically favored?
What is the consequence of being favored or unfavored?
What is the number of ATPs produced by th -
1. Favored
2. it's irreversible
3. 1.5-becuase FADH produces less than NADH -
In which organs is the Malate-Aspartate shuttle found?
What does it do?
Describe the pathway. -
1. heart and liver
2. takes electrons from cytosolic NADH and delivers them into the matrix
3. (picture shown - Is there a loss of free energy in the Malate-Aspartate shuttle system?
- No, since it starts with NADH in the cytosol and ends with NADH in the matrix
- where are the shuttle systems working (which membrane)?
- the inner membrane between the innermembrane space and the matrix
- What 5 things are required to convert oxaloacetate to aspartate (and or vice versa)?
-
1) Glutamate --> ∂-ketoglutarate(conjugate amino acids)
2) glutamate-oxaloacetate transaminase
3) ∂-ketoglutarate-malate carrier
4) malate dehydrogenase
5) aspartate-glutamate carrier - How many ATPs are being made by the Malate-Aspartate shuttle?
- 2.5
-
1- If the Malate-Asparte shuttle system is more efficient, why isn't it used all the time?
2- Is the Malate-Aspartate shuttle thermodynamically favored or unfavored?
3- What is the consequence of this? -
1- it requires a high NADH/NAD ratio in the cytosol (you can only use it when you don't really need it.)
2- thermodynamically neutral...
3- reversible - How many protons does complex I of the ETC transport per NADH?
- 4
- How many protons does complex II of the ETC transport per NADH?
- none
- How many protons does complex III of the ETC transport per NADH?
- 4
- How many protons does complex IV of the ETC transport per NADH? What is the yield in ATP for 1 NADH?
- 1) 2 Protons⬦ 2) 2.5 ATP
- 1) What is the total yield of ATP per FADH2?⬦ 2)Why?
- 1) 1.5⬦ 2) this is because the FADH2 is introduced at complex II (which does not export proton) and starts exporting protons at complex III
- How many moles of protons are need to make one mol of ATP?
- about 3
- how many kcals per mol of protons?
- 5.2
- What are the subunits for ATP synthase?
- F0 and F1
- Which subunit ejects protons and which makes ATP?
- F0: ejects protons⬦ F1: makes ATP
- What part of F0 actually ejects the proton?
- C
- What part of F1 is ultimately responsible for making ATP?
- gamma
- How do you get aspartic acid to enter membrane the ATP synthase and take with it a proton?
- Aspartic acid is negatively charged⬦ thus a proton neutralizes the aspartic acid which will now enter the membrane and take with it the proton
- what is the ratio of F0:a,b,c. And F1 ∂, ß, gamma, delta, and epsilon?
- F0: 1,2, 12⬦ F1: 3,3,1,1,1
- which subunits undergo a conformational change?
- ß
- Describe the state of the 3 ß subunits in F1.
- open (nothing in it), loose (ADP + Pi), tight (making ATP)
- What role does the gamma subunit play?
- it spins around and causes the ß subunits to change shape.
- In which ß state does the ATP that was made in the F1 subunit leave?
- open
- What happens if you reverse the direction of the gamma subunit rotation?
- you convert ATP into ADP + Pi
- what effect does oligomycin have on ATP synthase?
- it binds to and block the movement of protons through the F0 subunit and halts ATP production
- What effect does dinitrophenol have on the production of ATP? How does it have this effect?
- 1) it uncouples oxidative phosporylation by disapating the proton gradient⬦ 2) when in the innermembrane space it will be protonated --> move across the inner membrane --> deprotonate --> cross back across the membrane to the inner membrane space and do this until the proton gradient has dispated
- Which would cause a build up of NADH, slow down the TCA cycle and cause an increase in the proton gradient, oligomycin or dinitrophenol?
- oligomycin
- What is thermogenin?
- A natural oxidative phosphorylation uncoupler in the brown adipose tissue of infants and hibernating animals, which exhibits low ATP synthase activity and thus free energy is used to produce heat
- How does this work in hibernating animals?
- cold stimulus --> ß-oxidation of fats --> NADH --> thermogenin --> heat
- What is the role of translocase?
- It exchanges one ATP from the matrix, with one ADP from the cytosol
- Is there a cost associated with moving the ATP out of the matrix?
- yes, since ADP has a more negative charge , moving it into the matrix disapates the innermembrane charge⬦ thus 25%
- how many ATPs do humans and bacteria make per glucose? Why the inefficiency of eukaryotes?
- human: 30⬦ bacteria 38⬦ ATP translocation