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Unformatted text preview: Exam 3 Answer the following. Physical constants and a table of standard reduction potentials are located on the last page of the test. Graph paper is attached. Assume all temperatures are 37 o C . There are 103 points on this test. Good Luck. 1) Ascorbic acid (Vitamin C, below) acts as an antioxidant in vivo, helping protect the body against oxidizing. mutation-inducing chemical agents as well as against radiation. Oxidized ascorbate (dehydroascorbate) isn’t much use, however. Plants can use NADPH to reduce the oxidized form of ascorbate (dehydroascorbate) back to ascorbic acid as shown in the reaction below: Dehydroascorbate + NADPH + H + ⇌ Ascorbate + NADP + What is the equilibrium constant for this reaction? (Standard reduction potentials are on the last page) (6 pts) 2) The Krebs cycle produces both NADH and FADH 2 . Both transfer their electrons to the electron transport chain and becomes reoxidized. Each NADH produced in the Krebs cycle results in the production of (optimally) about 2.5 - 3 ATPs, while each FADH 2 produced in glycolysis only results in (optimally) about 1.5 - 2 ATPs. Explain why this is true. (5 pts) Electrons from FADH...
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This note was uploaded on 11/03/2010 for the course CH 369K taught by Professor Techniquesofresearch during the Spring '08 term at University of Texas.
- Spring '08