Practise AP Biology 3.5.B questions by tracing energy from glucose through glycolysis, the Krebs cycle and electron transport, then comparing fermentation.
To investigate how increases in environmental temperatures affect the metabolism of certain organisms, researchers incubated liver cells from toads at different temperatures and measured two markers of metabolic activity (Table 1): the rate of oxygen consumption and the rate of ATP synthesis.
Oligomycin is a compound that can block the channel protein function of ATP synthase. Predict the effects of using oligomycin on the proton gradient across the inner mitochondrial membrane.
Accept one of the following:
- The difference in the concentration of protons/pH (across the inner mitochondrial
membrane) will increase.
- There will be an increase in the concentration of protons/a decrease in pH in the
intermembrane space relative to that found within the mitochondrial matrix.
1 point
Justify your prediction.
Write your responses to this question only on the designated pages in the separate Free Response booklet.
If there are multiple parts to this question, write the part letter with your response.
Justify your prediction.
Accept one of the following:
- (Without protons being able to flow back into the matrix through ATP synthase), more protons will accumulate in the intermembrane space/between the two mitochondrial
membranes.
- (Without protons being able to flow back into the matrix through ATP synthase), there will be a lower pH in the intermembrane space/between the two mitochondrial
- Protons will not be able to flow across the membrane (through ATP synthase), but the electron transport chain will still pump protons into the intermembrane space.
1 point
Total for part (d)
for question 2
9 points