Question

can you explain 105 and 106

105. The electrons formed from the aerobic oxidation of glucose 1. Are ultimately transferred to oxygen ii. Are transferred to the coenzymes FAD and NAD 0, Are transferred to CO, during the citric acid cycle a. i only b. ii only c. i, ii d. ii, iii e. i, ii, iii 106. Which of the following is true regarding the complexes within the electron transport system? 1. Complex Il contributes twice as many protons to the gradient as Complex ii. Inhibition of Complex II would decrease the total number of electrons moving through the ETC iii. Inhibition of Complex II would not alter the amount of ATP generated from electrons originating from NADH a. i only b. ii only c. iii only d. i, ii e. i, ii, iii 107. Which of the prosthetic groups listed can accept or donate either one or two electrons due to the stability of the semiquinone state? a. Cytochromec b. NADH C. CoQ

Answer 1

105) the glucose is oxidized via glycolysis, pyruvate oxidation, and TCA cycle. the reduced coenzymes FADH2 and NADH formed during these processes carry the electrons from the glucose. FADH2 and NADH are oxidized via an electron transport chain, and the electrons are finally transferred to the oxygen and the oxygen is reduced to water.

so the answer is c) i, ii.

106) the complex I in the electron transport chain oxidizes NADH to NAD+, and electrons are transferred to coenzyme Q, complex I pumps 4 H+ from the matrix to the intermembrane space. complex II oxidizes the FADH2 and transfers the electrons to the coenzyme Q, complex II, does not pump any H+ to the intermembrane space, the coenzyme Q transfers H+ to the complex III and from complex III, cytochrome c carries electrons to complex IV where it is used to reduce oxygen. complex III and complex IV transfer H+ into the intermembrane space.

complex II transfers 2 electrons into the electron transport chain, so inhibiting the complex II will decrease the number of electrons passed through the electron transport chain, it also decreases the number of protons pumped into the intermembrane space by the complex III and complex IV. the H+ gradient is used to generate ATP by the ATP synthase so inhibiting complex II decreases the number of ATPs produced so the answer is b) ii only.