We have assumed that 4H+ are needed to synthesize one molecule of ATP, when the

Question

We have assumed that 4H+ are needed to synthesize one molecule of ATP, when the c ring has 10 subunits. Explain how this determined? Using the assumption from Q10 calculate the number of ATP molecules produced in the reactions catalyzed by the enzymes succinate dehydrogenase isocitrate dehydrogenase glyceraldehyde 3-phosphate dehydrogenase Determine the net ATP equivalents produced when each of the compounds below is oxidized completely to CO_2. (Use assumption stated in question 10) glucose pyruvate Fructose 1, 6 bis phosphate Glucose 6 phosphate dihydroyacetone phosphate acetyl CoA Identify and label the structure below. What are the function of these various elements in the structure. How is this related to ATP synthesis?

Explanation / Answer

10.
Comming to the question, the electron transport chain is made up of 5 complexes, Complex 1 NADH dehydrogenase, Complex 2 Succinate dehydroginase, Complex 3 Cytochrome bc1 complex, Complex 4 Cytochrome oxidase and Complex 5 ATP synthase.
Take the example of reducing equivalen NADH+H+. it enters the ETC at Complex 1. while going through the different complexes of ETC, 4 protons are transported from matrix side of mitochondria to intermembrane space at complex 1. 4 protons are transported at complex 3 and 2 protons at complex 3. So, when a single molecule of NADH+H+, is oxidised 10 protons are tranported from mitochondria matrix to intermembrane space, thereby generating electrochemical gradient. because of this gradient, the protons are protons are transported back to mitochondrial matrix through complex 5 (ATP synthase). The number of ATP synthesized upon the oxidation of 1 molecule of NADH+H+, is calculated by P/O ratio (The number of phosphates that are fixed into ATP for every two electrons that pass from a substrate relative to the atoms of oxygen reduced).
The most accepted value for number of protons required to drive the synthesis of an ATP molecule is 4, of which 1 is used in transporting Pi, ATP, and ADP across the mitochondrial membrane. Of10 protons are pumped out per NADH, 4 must flow in to produce 1 ATP, therefore proton-based P/O ratio is 2.5 for NADH as the electron
donor and 1.5 (6/4) for succinate.

11. Succinate dehydrogenase catatlyzes the conversion of Succinate into Fumarate with the release of 1 molecule of FADH2. FADH2 enters into ETC at complex 2, thus pumping out only 6 protons. Hence only 1.5 ATPs are generated
Isocitrate dehydrogenase catatlyzes the conversion of isocitrate into Alpha-keto glutarate with the release of 1 molecule of NADH+H+. As we already calculated, 2.5 ATPs are generated from the oxidation of 1 molecule of NADH+H+

Glyceraldehyde, 3-phosphate dehydrogenase converts Glyceraldehyde 3-phosphate into 1,3-Bisphosphoglycerate with the release of 1 NADH+H+. Hence, 2.5 ATPs are generated.

Glucose gives 32 ATPs
Pyruvate gives 12.5 ATPs
Fructose1,6 bisphoaphate give 34 ATPs
Dihydroxy acetone phophate give 34 ATPs
Glucose 6 phosphate gives 33 ATPs

Acetyle CoA gives 10 ATPs

13. ATP Synthase: ATP synthase is made up of two fractions, F0 and F1. F0 component is a transmembrane complex making up the proton pore and has three subunits in the proportion of A1 B2 C10-12. Whereas F1 complex is made up of 9 subunits of five different types, 3 alpha, 3 beta, 1 gama, 1 delta and 1 epslon. protons move through the pore of F0 component, that rotates the F1 which inturn catelyzes the formation of ATP

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