Question

8. Carbon monoxide (CO) is a colorless, odorless, and deadly gas. Carbon monoxide is deadly for a multitude of reasons. One reason is that it binds to Complex IV in the electron transport chain of mitochondria. By binding to Complex IV, CO prevents the complex from binding to oxygen and transmitting electrons to oxygen. a. What will happen to the electron transport chain if it can no longer pass electrons along to oxygen? (2 points) b. What will happen to the proton gradient produced by the electron transport chain in the presence of CO? (Think! Are protons still going against their concentration gradient in the presence of CO? Are they still going down their concentration gradient in the presence of CO?) (3 points) C. What process can still take place to produce ATP for the cell? Where does this process take place? (2 points) d. If ATP can still be made, then why does the cell eventually die? (3 points)

Answer 1

A) I'd there is no transport of electrons to the oxygen than oxidation of NADH and FADH2 will stop. As this oxygen molecule act as final electron acceptor in the ETC. So if electrons are not transported to oxygen than ETC will not work in the cell, there will be no protin motive force and no ATP formation.

B) as treatment of cell with CO inhibits complex IV and in turn tranport of electrons through chain. So it is the tranport of electrons where energy is released at some complex in enough amount. And this released energy is used to transport proton in to intermembrane space. If complex IV not work than ETC will not work , no oxidation of reducing equivalents and tranport of protons and absence of generation of proton motive forces ( PMF).

C) in ce ATP formation occur by 2 process

Substrate level phosphorylation- with out involved ETC, energy directly captured in form of ATP.

Oxidative phosphorylation- occur in mitochondria involving ETC

So in absence of ETC, substrate level phosphorylation still work which produces ATP in the cell.

D) ATP produced by substrate level phosphorylation is in very small amount and this amount of ATP is not sufficient to sustain basal metabolic rate of cell and ce eventually die. While energy produced by ETC in large amount.