Module 3 Topic 4: Transport Across the Inner Membrane Systems

13 flashcards · Other · by Haroon Chehabzada

1. What specific transport systems are found in the inner mitochondrial membrane?

   The inner membrane systems contain specific transport systems for the substrates of matrix oxidation and tricarboxylic substrates.

2. What is the role of the adenine nucleotide translocase in the mitochondrial membrane?

   The adenine nucleotide translocase transports ADP into the matrix in exchange for ATP.

3. What is the role of the phosphate translocase in the mitochondrial membrane?

   The phosphate translocase cotransports H2PO4 into the matrix and OH out.

4. What are some of the enzyme transporters found in the mitochondrial membrane?

   Enzyme transporters in the mitochondrial membrane include oxaloacetate, fumarate, malate, and succinate.

5. What conditions are necessary for chemiosmotic coupling to occur in the mitochondria?

   Favourable conditions for chemiosmotic coupling to occur require an intact inner mitochondrial membrane and key transporters spanning the membrane to the intermembrane space.

6. How does the process of respiration involve the transport of H+ ions in the mitochondria?

   The process of respiration involves transport of H+ ions out of the matrix in the mitochondria through the inner membrane via Complex IV and ATP Synthase.

7. Why does the inner membrane of the mitochondria need to remain impermeable to unidirectional H+ transport?

   The inner membrane of the mitochondria needs to remain impermeable to unidirectional H+ transport to allow a proton gradient to form.

8. What can happen if the inner membrane of the mitochondria is disrupted?

   Disrupting the inner membrane of the mitochondria can cause leakage of protons and electrons, leading to free radical production.

9. What happens if any mechanism in respiration is inhibited at any point?

   Inhibiting any mechanism in respiration at any point leads to a build-up of molecules prior to the block.

10. What is the P/O ratio and what conditions are required for it to occur?

    The P/O ratio requires a gradient where [protons] are higher in the intermembrane space than the matrix. Values for P/O ratio for NADH is 3 (or 2.5) and FADH2 is 2 (or 1.5).

11. How much energy is produced through the oxidation of NADH by O2?

    Oxidation of NADH by O2 produces energy enough to drive the synthesis of several molecules of ATP.

12. What is the efficiency of oxidative phosphorylation?

    The process of oxidative phosphorylation is not 100% efficient, with a typical efficiency of 42% for NADH and 53% for FADH2.

13. How much ATP is generated from the oxidation of one glucose molecule after glycolysis, TCA cycle and chemiosmotic coupling?

    The net energy yield for one glucose molecule after glycolysis, TCA cycle, and chemiosmotic coupling generates 4 ATP directly plus 10 moles of NADH and 2 moles of FADH2, which adds up to 38 ATP/mole glucose, with the net yield generally being 36 ATP/glucose due to oxidation of cytosolic NADH.