Cell Respiration Agenda and Homework Reminders

1. Agenda 10/3/11 • Study for Enzyme quiz while I check Lab 2 Handout • AP Lab 2 Report Format • Grade Free Response Questions • Enzyme Quiz • Intro Cell Resp and Photosynthesis as Reverse Metabolic Pathways Homework – Get theme book up to date and bring tomorrow AP Lab 2 Report due Wed. 10/5 Ch. 9 Cornell Notes and self-quiz due Monday 10/10 Quiz on Cell Respiration Monday 10/10

2. Agenda 10/4/11 • Review Theme examples so far • Video and discussion of Cellular Respiration pathways as redox reactions – glycolysis and Kreb’s Cycle • Start Cell Respiration poster Homework – AP Lab 2 Report due Wed. 10/5 Ch. 9 Cornell Notes and self-quiz due Monday 10/10 Quiz on Cell Respiration Monday 10/10

3. Agenda 10/5/11 • Collect lab reports • Continue working on posters – memorizing as you go Homework - Ch. 9 Cornell Notes and self-quiz due Monday 10/10 Quiz on Cell Respiration Monday 10/10

4. Agenda 10/6/11 • Finish and discuss Cell Respiration posters – glycolysis and Kreb’s cycle (20 min- use my notes and slide pictures) Homework - Ch. 9 Cornell Notes and self-quiz due Monday 10/10 Quiz on Cell Respiration Monday 10/10

7. Moving into matrix – on your picture, point to matrix, cristae, inner mitochondrial membrane, and intermembrane space

8. NADH from glycolysis also shuttles in here- 2ATP vs. 3 ATP per NADH depending on which shuttle working

11. Now moving to inner mitochondrial membrane

12. Fig. 9.15

13. Electrons carried by NADH are transferred to the first molecule in the electron transport chain, flavoprotein. • The electrons continue along the chain which includes several cytochrome proteins and one lipid carrier. • The electrons carried by FADH2 have lower free energy and are added to a later point in the chain. Fig. 9.13

14. The mechanism of ATP generation by ATP synthase is still an area of active investigation. • As hydrogen ions flow down their gradient, they cause the cylinder portion and attached rod of ATP synthase to rotate. • The spinning rod causes a conformational change in the knob region, activating catalytic sites where ADP and inorganic phosphate combine to make ATP. Fig. 9.14

15. Fig. 9.16

16. In alcohol fermentation, pyruvate is converted to ethanol in two steps. • First, pyruvate is converted to a two-carbon compound, acetaldehyde by the removal of CO2. • Second, acetaldehyde is reduced by NADH to ethanol. • Alcohol fermentation by yeast is used in brewing and winemaking. Fig. 9.17a

17. During lactic acid fermentation, pyruvate is reduced directly by NADH to form lactate (ionized form of lactic acid). • Lactic acid fermentation by some fungi and bacteria is used to make cheese and yogurt. • Muscle cells switch from aerobic respiration to lactic acid fermentation to generate ATP when O2 is scarce. • The waste product, lactate, may cause muscle fatigue, but ultimately it is converted back to pyruvate in the liver. Fig. 9.17b

18. Some organisms (facultative anaerobes), including yeast and many bacteria, can survive using either fermentation or respiration. • At a cellular level, human muscle cells can behave as facultative anaerobes, but nerve cells cannot. • For facultative anaerobes, pyruvate is a fork in the metabolic road that leads to two alternative routes. Fig. 9.18

19. Control of catabolism is based mainly on regulating the activity of enzymes at strategic points in the catabolic pathway. • One strategic point occurs in the third step of glycolysis, catalyzed by phosphofructokinase. Fig. 9.20

20. Carbohydrates, fats, and proteins can all be catabolized through the same pathways. Fig. 9.19

21. Let’s Practice Quiz • Use your poster and follow along as I ask questions.

22. Agenda 10/7/11 • Electron Transport Chain and Chemiosmosis, Regulation of C.R. and Fermentation • Practice Quiz • Discuss and sum up cell respiration with your partner – quiz each other • Hand back Lab 1 Reports and discuss Homework – Ch. 9 Cornell Notes and self-quiz due Monday 10/10 Quiz on Cell Respiration Monday 10/10