State where in the mitochondrion the electron transport chain is located.
Describe briefly the source of the electrons that are transferred along the electron transport chain.
Describe the role of oxygen in oxidative phosphorylation.
When a person has a stroke, blood supply to part of the brain is cut off, so some neurones get no oxygen. ATP generation by oxidative phosphorylation stops. Fig. 4.1 illustrates some of the effects of ATP shortage on a neurone in the brain.
Explain why the neurone membrane depolarises when the Na$^+$/K$^+$ pump stops operating.
Suggest why calcium ions rush into the neurone when the Na$^+$/K$^+$ pump stops working.
Suggest how shutting the ion channels in the neurones of the turtle at very low oxygen concentrations could enable the cells to survive.
Suggest what makes the amount of mRNA for protein channels decrease.