Biochemistry 2280A Lecture : ATP Synthesis

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orchidotter238

21 Dec 2011

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Electron transport chain is generated by a proton gradient. Things tend to go from an area of high concentration outside to an area of low concentration inside. Protons looking for a way to get back in atp synthase. Energetically favourable to want to get into the matrix. Outside is going to be positively charged while the inside is negatively charged. Electron transport chain is doing work pumping protons up hill. More protons on the top then the bottom diffuse from an area of high to low concentration this will drive them to go inside the matrix. The membrane potential is stronger main driving force. Protein complex shown allows a pathway for protons to go across the inner mitochondrial matrix is a tight seal. Protons need a special pathway to get across. Energetically favourable (proton motive force) will happen spontaneously drives rotation; the portion that stays stable drives adp to atp converted into chemical energy.

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.

There is a stable pH and electrical potential difference acrossthe mitochondrial membrane in

actively respiring cells. The pH of the cytoplasm is 6.8, the pHof the mitochondrial matrix (inside) is 8.3,

and the transmembrane potential is ?150 mV (inside negative).Calculate the free energy of transport

(?Gt) to move one mole of protons from the cytoplasm (outside)to the matrix (inside) under these

conditions and 37

cerisewallaby466

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

Biochemistry 2280A Lecture : ATP Synthesis

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