Answered: The formation of acetyl-CoA from… | bartleby

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

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The formation of acetyl-CoA from acetate is an ATP-driven reaction:

Acetate + ATP + CoA ⇌ Acetyl CoA + AMP + PPi

Calculate ΔG°' for this reaction given that the ΔG°' for the hydrolysis of acetyl CoA to acetate and CoA is −31.4 kJ mol⁻¹ (−7.5 kcal mol⁻¹) and that the ΔG°' for hydrolysis of ATP to AMP and PPi is −45.6 kJ mol⁻¹ (−10.9 kcal mol⁻¹).

ΔG°'reaction = ________ kJ mol⁻¹

The PPi formed in the preceding reaction is rapidly hydrolyzed in vivo because of the ubiquity of inorganic pyrophosphatase. The ΔG°' for the hydrolysis of pyrophosphate (PPi) is −19.2 kJ mol⁻¹ (−4.665 kcal mol⁻¹). Calculate the ΔG°' for the overall reaction, including pyrophosphate hydrolysis.

ΔG°'reaction with PPi hydrolysis = ________ kJ mol⁻¹

What effect does the presence of pyrophosphatase have on the formation of acetyl CoA?

- [ ] It does not affect the overall reaction.
- [ ] It brings the overall reaction closer to equilibrium.
- [ ] It makes the overall reaction even more exergonic.
- [ ] It makes the overall reaction even more endergonic.

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Imagine a triglyceride comprised of (3) saturated C12 fatty acids. Calculate the number of ATP generated from the complete oxidation of one of these 12-carbon fatty acids to CO2 and water in the liver. Assume that each NADH = 2.5 ATP and each FADH2 = ETC generates 1.5 ATP. Any step that yields pyrophosphate as a product should be treated as an input (i.e. net loss) of (2) ATP.
17.1 answer and explain
Acetyl-CoA AG" = -7.7 kcal/mol COA Fatty acids Oxaloacetate Citrate AG" = -1.5 kcal/mol Isocitrate Krebs cycle is equilibrium at 25°C with coupled fatty acid biosynthesis. Calculate the free energy of the fatty acid biosynthesis (in kcal/mol), accounting for the concentrations of Oxaloacetate – 0.005 mM; Acetyl-CoA - 0.03 mM; Citrate - 0.001mM and Isocitrate – 0.06 mM.
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