Cell Respiration 2023 AP BIOLOGY CHAP 4A

Cellular Respiration

1. Cell Respiration

2. Cell respiration is best described as a series of enzyme mediated biochemical reactions.

3. Because enzymes regulate the metabolism of the cell, they are carefully controlled by a variety of factors like: Temp pH Cofactors Coenzymes Compartmentalization within organelles AND Feedback inhibition! An enzyme’s activity is inhibited by the enzyme’s end product.

4. Feedback Inhibition

5. Important terms to know! Enzyme mediated biochemical pathway Substrate level phosphorylation vs Oxidative phosphorylation Enzyme meanings: Kinase: enzyme that catalyzes a reaction moving a phosphate from a phosphate donating molecule to a substrate. Ex. hexokinase Isomerase: catalyzes a conversion from one compound to an isomer of the compound Mutase: type of isomerase that moves a functional group from one position to another on same molecule Dehydrogenase: catalyzes the removal of water from a molecule

6. The Nature of Molecules

7. Glycolysis --found in both eukaryotes and prokaryotes In cytoplasm

8. GLYCOLYSIS Inputs: 1 glucose, 2 ATP Outputs: 2 pyruvates, 4 ATP, 2 NADH Location: Cytoplasm

9. Lactic Acid Fermentation takes place in cytoplasm No O2 available, so NAD+ cannot be regenerated from ETC Must find another way to regenerate NAD+ Found in: muscles when they run out of O2 red blood cells always (they don’t have mitochondria) bacteria that make yogurt

10. Alcohol Fermentation takes place in cytoplasm No O2 available, so NAD+ cannot be regenerated from ETC Must find another way to regenerate NAD+ Found in yeast most commonly

11. Pyruvate Oxidation—in the matrix of mitochondria

12. Pyruvate Oxidation Inputs: 2 pyruvates Outputs: 2 acetyl coA’s, 2 CO2, 2 NADH Location: Mitochondrial matrix

13. Kreb’s Cycle in matrix of mitochondria

14. Kreb’s Cycle--in the matrix of mitochondria

15. KREB’S CYCLE Inputs: 2 acetyl coA’s Outputs: 4 CO2’s, 6 NADH’s, 2 FADH2’s and 2 GTP’s Location: Mitochondrial matrix

16. Glycolysis, Pyruvate Oxidation & Kreb’s Glucose NAD+ NADH Pyruvate ATP FAD FADH2 Acetyl Co-A CO2 Location

17. Electron Transport Chain--inner mitochondrial membrane

18. For every NADH: Protein 1: 4 protons pumped through Protein 2: skipped Protein 3: 4 protons pumped through Protein 4: 2 protons pumped through TOTAL: 10 protons For every FADH 2 : Protein 1: skips Protein 2: 0 protons Protein 3: 4 protons pumped through Protein 4: 2 protons pumped through TOTAL: 6 protons

19. ATP Accounting for 1 molecule of glucose Glycolysis: 2 ATP + 2 NADH Pyruvate Oxidation: 2 NADH Kreb’s Cycle: 2 ATP (or 2 GTP, depending on cell type) 6 NADH 2 FADH 2 _ TOTAL ______________________________________________ 4 ATP (or its equivalent, including GTP) 10 NADH 2 FADH 2

20. ATP From NADH and FADH 2 For every NADH, 10 protons shoot through so, 10 NADH x 10 protons/each=100 protons It takes 3 protons to make 1 ATP so, 100 protons/3 = 33 ATP’s made from NADH For every FADH 2 , 6 protons shoot through so, 2 FADH2 x 6 protons/each=12 protons It takes 3 protons to make 1 ATP so, 12 protons/3= 4 ATP’s made from FADH 2

21. TOTAL ATP 4 total ATP from glycolysis + Kreb’s Cycle 33 from NADH 4 from FADH 2 _____________________________ Total=41 But the # can be anywhere from 28-40! Why?

22. But….. You should know now that mitochondria is the site of oxidative phosphorylation*. ** the process by which ATP synthesis is coupled to the movement of electrons through the mitochondrial electron transport chain and the associated consumption of oxygen

23. Bacteria can do ETC too!

24. Insert bacterial ETC pic here

25. Alternatives to oxygen as the final electron acceptor If oxygen is not available to be the final electron acceptor, then how can NAD+ be regenerated? Use something else as final electron acceptor! For example: reduce carbon dioxide to methane reduce sulfate to hydrogen sulfide Call this ANAEROBIC respiration

26. https://i1.wp.com/www.biogeologist.com/wp-content/uploads/Sully-Vent-Main-Endeavour-Vent-Field-Pacific-Ocean-NOAA.jpg?fit=2560%2C1920&ssl=1

27. Aerobic Respiration: Complete oxidation of glucose Oxygen is final electron acceptor Gly, Kreb, ETC 28-40 ATP’s produced Anaerobic respiration: Complete oxidation of glucose Something other than oxygen is final electron acceptor Gly, Kreb, ETC 28-40 ATP’s produced Fermentation partial oxidation of glucose 2 ATP’s produced Gly only Last ditch way to regenerate NAD+

28. What if glucose is low?

29. Amino acids can be converted for use in metabolism too!

30. https://mitochondrialdisease.nhs.uk/patient-area/what-mitochondrial-disease/