Chapter 18, Problem 41CQ

(a)

Summary Introduction

To explain: A simplistic interpretation of the Q cycle would predict that the proton pumping efficiency of cytochrome bc₁ would be reduced by not more than 50% in the presence of saturating amounts of antimycin A.

Concept introduction: Q cycle is a part of electron transport chain that helps for sequential transfer of electrons to oxygen in order to avoid the formation of oxy radicals. Antimycin A is antibiotic produced by Streptomyces that inhibits the electron transport chain of mitochondria.

(b)

Summary Introduction

To explain: The reason why cytochrome bc₁ is nearly inhibited by antimycin A.

Concept introduction: Antimycin A is antibiotic produced by Streptomyces that inhibits the electron transport chain of mitochondria. Cytochromes are electron carriers between complex III and complex IV of electron transport chain.