BIOL 204 Lecture Notes - Lecture 34: Atp Synthase, Electrochemical Gradient, Intermembrane Space

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sapphiredog573

4 Apr 2018

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Goal of cellular respiration is synthesis of atp. Nadh has more free energy than o2. Energy released during etc is used to do work to transport protons (proton pumping) across inner mitochondrial membrane, causes h+ to increase and ph lower in the intermembrane space electrons to complex iii, releases protons into intermembrane space. Complex i and iv use the energy released from etc for proton pumping. Ubiquinone accepts electrons from complex i and ii and protons, donates. When one side of inner membrane has more protons than other this is. Nadph by etc, generation of atp in chloroplasts driven by light: chemiosmosis does synthesis of atp but also pumps substances across membranes and drives rotation of flagella in prokaryotes. Oxidative phosphorylation mode of atp synthesis that is linked to oxidation of energy-rich molecules by etc, relies on action of atp synthase. Proton-motive force moves protons from intermembrane space through basal unit channel down concentration gradient into matrix.

Related Questions

1. Compared to the generation of ATP by oxidative phosphorylation, what is a major difference in mechanism of ATP generation by substrate-level phosphorylation in glycolysis?

A. A proton gradient is not involved

B. The ATP produced has less energy content because oxygen was not involved.

C. Substrate level phosphorylation occurs in the inter-mitochondrial space

D. One can't generalize without knowing the substrate.

2. Which of the following statements is true?

A. Because the electrons in NADH are at a higher energy than the electrons in reduced ubiquinone, the NADH dehydrogenase complex can pump more protons than can the cytochrome b-c1 complex.

B.The pH in the mitochondrial matrix is higher than the pH in the intermembrane space.

C. The proton concentration gradient and the membrane potential across the inner mitochondrial membrane tend to work against each other in driving protons from the intermembrane space into the matrix.

D. The difference in proton concentration across the inner mitochondrial membrane has a much larger effect than the membrane potential on the total proton-motive force.

Oxidative phosphorylation is the final stage of cellular respiration and the main pathway of aerobic energy generation from glucose. Which of the following statements is NOT true?

a. NADH and FADH2 are used as âinputâ into the electron transport chain

b. The electron transport chain produces a proton gradient across the inner mitochondrial membrane

c. FADH2 stores less energy than NADH

d. The electron transport chain is made up of several membrane protein complexes

e. ATP synthesis by chemiosmosis requires about 30 protons per ATP molecule

The free energy of ATP synthesis from ATP synthase under cellular conditions is +45 kJ/mol.

a. Where does the energy come from?

b. If the pH of the matrix is 7.84, the intermembrane space is 7.16 and the membrane potential is +/- 0.15 V at 37 C, how much energy can be produced from this gradient per mol of protons?

c. How many moles of protons moving across this gradient would be required to produce enough energy for one mole of ATP to be synthesized?

d. To generate a proton gradient the mitochondria use the energy of electron transport. How much energy is produced in the oxidation of NADH by oxygen (under standard biochemical conditions)?

e. Using the answer from b, how many moles of protons could be transported out of the matrix with this oxygen energy (d)?

f. How many moles of protons are actually transported in the oxidation of NADH theough the ETC?

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BIOL 204 Lecture Notes - Lecture 34: Atp Synthase, Electrochemical Gradient, Intermembrane Space

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