Question #fc1c7

1 Answer
BillytheKid
Jan 19, 2018

It grinds to a halt..

Explanation:

The final stage of cellular respiration is the electron transport chain. The electrons are passed via 3 large protein complexes (Complex I to Complex III), finally to arrive at Complex IV .

This enzyme, Cytochrome C Oxidase, or COX, finally passes the electrons over to Oxygen, forming #H_2O# in the process.

In the Active site are two haem-groups present (cytochromes #a# and #a_3#), along with two Copper centres (#Cu_a and Cu_b#). These centres are the docking sites for the Oxygen molecules.
Unfortunately, just like Carbon Monoxide, Cyanide has a stronger affinity for these centres than Oxygen does. and therefore binds competitively, and irreversibly, to the active #"Cytochrome " a_3-Cu_b # centre. It thereby prevents Oxygen molecules from docking, and the ETC grinds to a halt...

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