Question

1. Please review the concept of standard reduction potential and answer the following question (1 point) Ubiquinone (Q) and cytochrome care components of the Electron Transport Chain (ETC). Their standard reduction potentials are listed below: Q+ 2H+ + 20 → QH2, AE = +0.045 V Cytochrome e (Fe)+H+ Cytochrome c (Fe?), AE = +0.254 V For the following net reactions, please circle the reaction that can occur spontaneously under standard conditions and in this reaction, please circle the reactant being reduced. a. QH2 + 2 Cytochrome c (Fe?') + 2 Cytochrome e (Fe +Q b. Q+ 2 Cytochrome e (Fe) → QH2 + 2 Cytochrome c (Fe?") c.Q+2 Cytochrome c (Fe) → 2 Cytochrome e (Fe) + QHz d. QH; + 2 Cytochrome c (Fe) → Q+ 2 Cytochrome e (Fe?") OH OH HO HO HO -0% OOH CAJCircle the anomeric carbons in each of the three sugars (point BibScribe the two linkages Use numbers and greek letters eg. -12)Please follow the rule described in class. Il point)

Answer 1

Reaction takes place as follow Q+ 2H+ +2e -> Q41 = +0.0450 - 0 Cy to chrome c (Fe3+) +*+/- → Cyto chrome c CFezt) DE° -0.284 - multiply ep. ① by 2 2 cylochromec (Fe3) + 24*+2e" -> 2cy to chrome c (fedt) DE° = 0.254 v - For a reaction To be spontenous, or should be positive DE>o oxidation half reaction - Q42 Q+24+ the De = -0.045 If we reverse ep. the sign of se also changes so oxidation half reaction Q4, Q +24++ 26 DE = -0.045 2 Cyclo Chromec (Fe 3") +244 +ae- → 2 Cytochrome c (fero) DE°= 0.2 syv et reaction Q4g + Quy crochrome Lfe3") 444> Q + 2y to chrome c (fe 2)

Q42 + 2ly to chrome (Fe3+) - Q+ 2 cytochrome C(Feay DE reechin - De oxidation & De reduction polentine potential -0.0450 + 0.252 = 0.209 v De so so obrim a correct.