Metabolism Module 2 Topic 4: Anaplerotic Reactions

29 flashcards · Other · by Haroon Chehabzada

1. What does the inner membrane system contain specific transport systems for?

   The substrates of cytosol.

2. What is transported by the pyruvate transport system?

   Pyruvate to the matrix.

3. What does the dicarboxylate transport system exchange?

   Succinate, fumarate, and malate for other orthophosphates.

4. What does the tricarboxylate transport system couple?

   Citrate and isocitrate with each other or other dicarboxylic acids.

5. What is transported by the adenine nucleotide translocase and in exchange for what?

   ADP into the matrix in exchange for ATP.

6. What does the phosphate translocase cotransport into the matrix and out?

   H2PO4 into the matrix and OH out.

7. What enzyme transporters are included in the inner membrane system?

   Oxaloacetate, fumarate, malate, and succinate.

8. What conditions are favorable for chemiosmotic coupling?

   Intact inner mitochondrial membrane.

9. Where does the energy-yielding process of the electron transport chain (ETC) take place?

   In mitochondria.

10. How are H+ ions transported from the matrix of the mitochondria to the intermembrane space?

    Through the inner mitochondrial membrane.

11. What drives the synthesis of ATP in mitochondria?

    The transport of H+ ions from the matrix to the intermembrane space.

12. What do uncouplers do to the electron transport chain?

    They disrupt the favorable conditions by allowing H+ ions to leak back into the matrix, uncoupling the ETC from ATP synthesis.

13. What is the P/O ratio, and why is it crucial in determining the amount of ATP generated by redox reactions in mitochondria?

    The P/O ratio is the ratio of ATP molecules produced to oxygen atoms consumed. It is crucial because it determines how efficiently the energy from redox reactions is converted into ATP. NADH has a P/O ratio of 3 or 2.5, and FADH2 has a P/O ratio of 2 or 1.5.

14. How much free energy is generated by the oxidation of NADH by O2, and what does it drive?

    -220 kJ/mol of free energy is generated, which can drive the synthesis of several molecules of ATP.

15. Does the ETC's chemiosmotic coupling work at 100% efficiency, and why or why not?

    No, it does not work at 100% efficiency due to electron and proton leakage.

16. How is ATP produced in mitochondria, and how many ATP molecules can be generated per mole of glucose?

    ATP is produced through oxidative phosphorylation, which involves glycolysis, the TCA cycle, and chemiosmotic coupling of ETC, generating up to 38 ATP/mole glucose.

17. How is dihydroxyacetone I phosphate (DHAP) produced in the cytosol?

    DHAP is produced in the cytosol via aldolase and isomerase from glyceraldehyde 3-phosphate.

18. What produces Glycerol 3-phosphate in the matrix, and what does this process require?

    Glycerol 3-phosphate dehydrogenase (mGPDH) produces Glycerol 3-phosphate in the matrix, and this process requires FAD as an alternative regeneration of NADH for glycolytic processes.

19. Where does Glycerol 3-phosphate dehydrogenase transport electrons from DHAP?

    Glycerol 3-phosphate dehydrogenase transports electrons from DHAP to NADH in the mitochondrial matrix (N side).

20. How does NADH enter the electron transport chain?

    NADH enters the electron transport chain as an FADH2.

21. What is the energy yield of the conversion of glucose to two pyruvate molecules?

    The energy yield is 2 ATP and 2 NADH.

22. How do the Malate/Aspartate shuttle and Glutamate shuttle help transport electrons to the mitochondrial matrix?

    The Malate/Aspartate shuttle and Glutamate shuttle help transport electrons to the mitochondrial matrix, and each process produces NADH.

23. What does acetyl CoA combine with to form citrate?

    Acetyl CoA combines with oxaloacetate to form citrate.

24. What energy carriers and electron carriers are produced by the TCA cycle?

    The TCA cycle produces energy carriers and electron carriers such as 2 ATP, 6 NADH, and 2 FADH2.

25. Where do the electron carriers (NADH, FADH2) donate electrons in the mitochondria?

    The electron carriers (NADH, FADH2) donate electrons to the electron transport chain in the inner mitochondrial membrane.

26. What does the electron transport chain generate, and what is it used for?

    The electron transport chain generates a proton gradient, which is used by ATP synthase to produce ATP.

27. What is the P/O ratio, and what does it depend on?

    The P/O ratio is the ratio of ATP molecules produced to the number of electrons transferred from NADH to O2, and it depends on the ATP yield.

28. What affects the regulation of central pathways, and how can regulation be affected?

    Cellular ATP requirements and glucose requirements affect the regulation of central pathways, and regulation can be affected by the availability of ADP, Pi, and oxygen.

29. What stimulates phosphofructokinase, and what inhibits it?

    Fructose-6-phosphate stimulates phosphofructokinase, while fructose-1,6-bisphosphate inhibits it.