Oxidative phosphorylationEdexcel A-Level Biology B: Flashcards

What these 13 flashcards ask

Where does oxidative phosphorylation take place?
What supplies electrons to the electron transport chain?
How is energy released along the electron transport chain?
What is the energy from the electron transport chain used for?
What is a proton gradient?
What is chemiosmosis?
What is the role of ATP synthase?
What is the role of oxygen in respiration?
What happens to the electron transport chain without oxygen?
Why does the Krebs cycle stop without oxygen?
Why is the inner membrane folded into cristae?
Why must the inner membrane be impermeable to protons?
Why is the intermembrane space narrow?

Exam questions on Oxidative phosphorylation

Isolated mitochondria are suspended in a buffered medium containing a pH electrode. The outer membranes of the mitochondria are permeable to small ions. When NADH and oxygen are added, the pH of the medium falls, and ATP is formed if ADP and phosphate are also present.
Explain why the pH of the medium falls after NADH and oxygen are added.2 marks
A researcher adds a chemical to isolated mitochondria that makes the inner membrane freely permeable to protons. Electrons continue to pass along the electron transport chain, and oxygen continues to be used at a high rate, but ATP production almost stops.
Explain why ATP production almost stops.2 marks
Cyanide binds to the last protein carrier in the electron transport chain and prevents it from passing electrons to oxygen. Cells exposed to cyanide soon run short of ATP, even though plenty of glucose is available. The Krebs cycle in these cells also stops.
Explain why cells exposed to cyanide soon run short of ATP.3 marks

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).