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Oxidative phosphorylationAQA A-Level Biology: Flashcards

What these 12 flashcards ask

  • Where does oxidative phosphorylation occur?
  • What is oxidative phosphorylation?
  • Which enzyme makes ATP in oxidative phosphorylation?
  • What do reduced NAD and reduced FAD do at the electron transfer chain?
  • What is the energy from the electrons used for?
  • What is the proton gradient?
  • How are protons moved back into the matrix?
  • What is chemiosmosis?
  • What is the role of oxygen?
  • What happens to the electron transfer chain without oxygen?
  • Why are cristae important?
  • What happens if the inner membrane becomes leaky to protons?

Exam questions on Oxidative phosphorylation

  1. Mitochondria were isolated from heart muscle and the processes taking place at their inner membranes were investigated.
    Describe the role of reduced NAD in oxidative phosphorylation.2 marks
  2. In respiring mitochondria the intermembrane space is found to be more acidic than the matrix.
    Explain why the intermembrane space is more acidic than the matrix in respiring mitochondria.2 marks
  3. Two inhibitors are added, separately, to suspensions of respiring mitochondria that are supplied with reduced NAD and oxygen. Inhibitor X blocks the channel in ATP synthase so that protons cannot pass through it. Inhibitor Y blocks the last carrier of the electron transfer chain so that electrons cannot be passed to oxygen.
    Predict the effects of inhibitor X on ATP synthesis, on the proton concentration in the intermembrane space and on oxygen consumption, giving reasons.3 marks
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Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).