Question

Action of metabolic processes:

Oligomycin - Binds and blocks the proton channel in ATP synthase

Carbon monoxide - Inhibits cytochrome oxidase

2,4-dinitrophenol (DNP) - Binds protons and moves them down their electrochemical gradient

Rotenone - Blocks electron transfer at NADH dehydrogenase

Explain how these metabolic poisons affect different processes during cell respiration?

- Effect on electron transport (increased, decreased, no effect) and why

- Effect on ATP synthesis (increased, decreased, no effect) and why

Answer 1

A) oligomycin effect -- decreased electron transport

Decreased ATP synthesis

As it inhits Fo subunit of ATP synthase complex thus prevent entry of protons in to mitochondria matrix from intermembrane space. Thus inhibits oxidative phosphorylation ( both oxidation as well as phosphorylation means synthesis of ATP)

B) CO poisoning

Decreased electron transport

Decreased ATP synthesis

It inhibits cytochrome oxidase , which converts oxygen in to water . Thhu it inhibits electron tranport chain, due to this no protibs are pumped and in lack of proton motive force no ATP synthesized

C) 2, 4 DNP

Electron transport normal / no effect

ATP ATP syntesis decreased

2, 4 DNP act as uncoupler, it do not affect ele tein transport in chain . It disaapiate the protin gradient which is required for ATP synthesis. Thus in absence of PMF no ATP will be synthesized.

D) rotenone

Electron transport decreased

ATP syntesis decreased

This is complex I inhibitor ( NADH COQ reductase) thus inhibits transport of electrons through the chain