Biochem Exam 3 Lecture 1 MCPHS
Questions With Correct Answers.
What is the final stage of cellular respiration and where does it happen - answer✔✔Oxidative
phosphorylation, in the mitochondria
What does oxidative phosphorylation couple - answer✔✔The oxidation of NADH or FADH2 to
the reduction of O2 to get H2O and formation of ATP
Where in the mitochondria are the components of the respiratory chain - answer✔✔Inner
membrane
Briefly summarize the process of the respiratory chain - answer✔✔1. Electrons flow through a
chain of membrane-bound carriers
2. This results in protons (H+) pumped from matrix to inter membrane space
3. H+ gradient drives ATP synthesis
Electrons are transferred from a substrate to which universal electron acceptors -
answer✔✔NAD+, NADP+, FAD, FMN
NAD+ or NADP+ accepts what and releases what, how many electrons at once -
answer✔✔Accepts H- (H+ and 2 electrons), picks up a pair of electrons at once, releases a
proton
How many electrons can FAD or FMN accept and transfer at a time - answer✔✔One or two
electrons AT A TIME
What are the other sequentially acting electron carriers in the respiratory chain besides NAD and
flavoproteins - answer✔✔Hydrophobic quinone (ubiquinone, Q), Cytochrome (contain iron),
Iron-sulfur proteins
Describe the characteristics of ubiquinone AKA Coenzyme Q [Q] - answer✔✔Lipid-soluble,
small, freely diffusible (can move around everywhere)
How many electrons can Q accept and what does it carry - answer✔✔Accepts 1 or 2 electrons,
carries a proton with each electron