8.2 Cell Respiration

The diagram shows the electron transport chain in the membrane of the mitochondria.

Cyanide is a poison which causes cell death through inhibition of the final electron transport protein when it binds as shown in the diagram.

Which statements correctly describe the impact of cyanide binding to the final transport protein.

1. A decrease in pH of the intermembrane space
2. A decrease in production of H₂O
3. An increase in electrochemical gradient
4. Inhibition of ATP synthesis

From each molecule of substance X (in the diagram), how many molecules of ATP can be produced?

Which of the following statements about the Krebs cycle are correct?

1. NAD is oxidised and returned to the link reaction
2. Citrate is decarboxylated to form a 6 carbon molecule
3. FADH₂ is produced and sent to the electron transport chain
4. Oxidation of acetyl groups is coupled to reduction of hydrogen carriers.

The following steps describe processes involved in oxidative phosphorylation.

1. Redox reactions drive the movement of protons across the cristae to the intermembrane space
2. Oxygen molecules combine with protons and electrons to form water
3. NADH and FADH donate electrons to the first transport protein in the chain
4. Hydrogen ions (protons) are also released as the coenzymes are oxidised
5. A high concentration of protons in the intermembrane space creates an electrochemical gradient
6. Electrons move down the proteins in a series of redox reactions
7. Protons move down the electrochemical gradient through enzyme ATP synthase

Which of the following shows the correct sequence for these steps?