1. Biol 121, Fall 2010, Tom Buckley 06 Oct 2010 capture: photosynthesis use: respiration Bioenergetics: energy and carbon flow

2. Q: Which direction will water move? (a)from left to right (b)from right to left  s = -3.6  s = -0.5  p = +2.6  p = +0.5 Cell #1 (LEFT) Cell #2 (RIGHT)

3. we have: light, CO 2, H 2 O Photosynthesis we want: carbohydrate

4. Chloroplast Thylakoid leaf mesophyll cells }

5. Photosynthesis: steps 1. water splitting chlorophyll photon is absorbed electron is ejected + + charge makes chlorophyll a strong oxidant

6. Photosynthesis: steps 1. water splitting chlorophyll + + charge makes chlorophyll a strong oxidant reductant : donates electrons oxidant : takes electrons away

7. Photosynthesis: steps H-O-H 1. water splitting chlorophyll + charge makes chlorophyll a strong oxidant electron is stripped from water H + O 2 +

8. Photosynthesis: steps 2. electron transport electron is ejected electron transport chain NADP H NADP +

9. Photosynthesis: steps 2. electron transport electron transport chain

10. Photosynthesis: steps 2. electron transport Concentration gradients are a form of energy H+H+ ADP ATP

11. Photosynthesis: steps 2. electron transport electron is ejected ADP ATP electron transport chain NADP + NADPH

12. Q: Where do the electrons that reduce NADP + originally come from? (a)water (b)CO 2 (c)oxygen (d)sunlight ADP ATP NADP + NADPH

13. Q: Is water reduced or oxidised in photosynthesis? (a)reduced (b)oxidised ADP ATP NADP + NADPH

14. Stoma CO 2 photosynthesis Photosynthesis: steps CO 2 Calvin cycle 3. Calvin cycle NADPH ATP NADP + ADP sugar

15. Photosynthesis: steps 3x CO 2 3x RuBP (5C) 6x PGA (3C) 3. Calvin cycle 6 NADPH 6 ATP 6x PGal (3C) 6 NADP + 6 ADP sucrose & starch 3 ATP 3 ADP 1/6 5/6

16. Photosynthesis: stepsside note: fluorescence NADPH NADP + X photon

17. Calvin cycle Photosynthesis: steps carbon fixation CO 2 RuBP 2x PGA enzyme: Rubisco most abundant protein on Earth ~half of N in leaves big, slow

18. Calvin cycle CO 2 RuBP 2x PGA Photosynthesis: steps photorespiration: O 2 fixation enzyme: Rubisco most abundant protein on earth ~half of N in leaves big, slow also fixes oxygen O 2 RuBP PGlyc + PGA carbon lost energy consumed

19. Photosynthesis: overview 1. water splitting: provide energetic electrons 2. electron transport: generate ATP & reductant (NADPH) 3. carbon fixation: attach (fix) CO 2 to organic molecule 4. carbon reduction: use NADPH to reduce the fixed carbon

20. Photosynthesis: overview Light reactions Calvin cycle 1. water splitting: provide energetic electrons 2. electron transport: generate reductant (NADPH) & ATP 3. carbon fixation: attach CO 2 (from air) to organic molecule 4. carbon reduction: use NADPH to reduce the fixed carbon

21. Photosynthesis: importance All the energy that fuels nearly all life All the carbon that nearly all life is built from

22. Group exercise H2OH2O O2O2 H+H+ e-e- NADPH NADP + e-e- ADP ATP H+H+ H+H+ H+H+ e-e- pH is a measure of H + concentration. Low pH means high H + concentration. If we isolated thylakoids and put them in low and high pH solutions, in which solution would thylakoids produce more ATP? photon

23. Jagendorf experiment H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ low pH H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ high pH + ADP, P i H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ ADP PiPi PiPi PiPi PiPi H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ ATP ATP formed!

24. Q: What is the enzyme responsible for CO 2 fixation called? (a)Nabisco (b)Rubisco (c)ConAgra (d)Viagra (e)Beatrice CO 2 RuBP 2x PGA

25. ATP ADP Respiration electron transport chain in mitochondria NAD + CO 2 sugars NADH H2OH2OO2O2 Krebs cycle

26. ADP Photosynthesis electron transport chain electron is ejected ATP NADP + NADPH CO 2 sugars in chloroplasts H2OH2OO2O2 Calvin cycle

28. Aerobic respirationPhotosynthesis CO 2 CH 2 O oxidation ATP ADP energy electrons O2O2 H2OH2O ATP ADP CO 2 CH 2 O reduction solar energy electrons O2O2 H2OH2O ATP ADP

29. Aerobic respirationPhotosynthesis CO 2 CH 2 O oxidation ATP ADP O2O2 H2OH2O CO 2 CH 2 O reduction O2O2 H2OH2O

30. Preparing for next test Online Quiz: available soon Ch 10 Self-Quiz (# 1, 2, 5, 7, 9) Ch 29 Self-Quiz (# 3, 4, 8, 9, 11) Ch 35 Self-Quiz (# 3, 4, 6, 8) Ch 36 Self-Quiz (# 2, 3, 7)