The effect of the drug fluoxetine (Prozac) on isolated rat brain mitochondria was examined by measuring the rate of electron transport in the presence of various concentrations of substrates and inhibitors. Use the following information to answer the questions posed below. Pyruvate and L-malate, are substrates that exhibit a P:O ratio of 2.5. Succinate is a substrate that exhibits a P:O ratio of 1.5, while tetramethylpara-phenylene diamine (TMPD) is a substrate that donates 2 electrons directly to Complex IV and exhibits a P:O ratio of 1. Rotenone is a plant toxin that blocks electron transport at Complex I. Required:
a. How do pyruvate and L-malate serve as substrates for electron transport?
b. How does fluoxetine effect the electron transport chain (ETC) and at which specific step(s)?