Question

In the lab, metabolic poisons can be used to study ATP synthesis and oxygen consumption. Many of these poisons have – or have had – other uses, from diet aids to animal poisons to antibiotics. Poison Action oligomycin binds to F0F0 and blocks the proton channel cyanide inhibits cytochrome oxidase by reacting with heme a3 trifluorocarbonylcyanide phenylhydrazone (FCCP)(FCCP) increases membrane proton permeability rotenone blocks electron transfer at NADHNADH dehydrogenase (NAD−Q(NAD−Q oxidoreductase) bongkrekic acid binds to inward‑facing site of ATP‑ADP translocase Classify the metabolic poisons as electron transport inhibitors, uncoupling agents, ATP synthase inhibitors, or transport inhibitors.

Answer 1

Answer:

Electron transport inhibitors: Cyanide, Rotenone

Uncoupling agents: trifluorocarbonylcyanide phenylhydrazone (FCCP)(FCCP)

ATP synthase inhibitors: Oligomycin

Transport inhibitors: Bongkrekic acid

Explanation:

Electron transport inhibitors: Cyanide, Rotenone

Cytochrome oxidase also known as complex IV in the electron transport chain, carries electrons from cytochrome c to oxygen. It is a large enzyme having 13 subunits. Subunit  1 contains  two heme groups , a and a3. Electrons are tranferred from heme a to oxygen bound to heme a3. The reaction of cyanide with heme a3 blocks this process of eleron transport

.Rotenone blocks electron transfer at NADH dehydrogenase (NAD−Q(NAD−Q oxidoreductase) by preventing electron transfer from Fe-S center to ubiquinone.

Uncoupling agents: trifluorocarbonylcyanide phenylhydrazone (FCCP)(FCCP)

The transfer of electrons  from NADH through the respiratory chain to molecularoxygen is coupled to proton pumping from the inner mitochondrial matrix to the intermembrane space. This generates a proton motive force which is utilized in ATP synthesis. Trifluorocarbonylcyanide phenylhydrazone (FCCP)(FCCP) increases membrane proton permeability, causing protons to leak back into the mitochondrial matrix, thereby uncoupling the processs of ATP synthesis and proton flux.

ATP synthase inhibitors: Oligomycin

ATP synthase is the enzyme rensponsible for ATP synthesis. It has two functional domains,: F₁ and F₀. Oligomycin binds to F₀ and blocks the proton channel preventing rotation of the F₁ subuni, thus, preventing ATP synthesis from ADP.

Transport inhibitors: Bongkrekic acid

Adenine  nucleotide translocase is a transport protein that  transports free ADP from the cytoplasm into the mitochondrial matrix, while ATP produced from oxidative phosphorylation is transported from the mitochondrial matrix to the cytoplasm o the cell.

Bongkrekic acid inhibits Adenine nucleotide translocase, thus preventing ATP from leaving the mitochondria and starving cells of needed energy.