The question
Name: ______________________ Date: ____________ Three chemicals that act on mitochondria (4 points)
Experimental setup
Three chemicals that act on mitochondria
In the inner mitochondrial membrane, an electron transport chain passes electrons from NADH and FADH₂ to O₂ and pumps H⁺ into the intermembrane space; ATP synthase uses the H⁺ gradient to make ATP. Three chemicals affect this system. Rotenone, a pesticide, blocks the first protein of the chain, which accepts electrons from NADH. Oligomycin blocks the H⁺ channel of ATP synthase. 2,4-Dinitrophenol (DNP) carries H⁺ across membranes; in the 1930s it was sold as a diet pill, and some people who took it died of dangerously high body temperature.
(a) Describe the role of O₂ in the electron transport chain. [1 point]
(b) Explain why adding oligomycin to isolated mitochondria reduces their O₂ consumption, even though oligomycin does not act on the electron transport chain. [1 point]
(c) Predict the effect of DNP on the amount of ATP a cell makes and on body temperature. Justify your prediction. [1 point]
(d) Cells treated with rotenone produce much more lactate than untreated cells. Explain this observation. [1 point]