2. PHOTOSYNTHESIS: OVERALL REACTION 6CO 2 + 6H 2 0 C 6 H 12 O 6 + 6O 2 Light, Chlorophyll

3. PHOTOSYNTHESIS: LIGHT REACTIONS VS. DARK REACTIONS THE FUNCTION OF THE LIGHT REACTIONS IS TO CONVERT SUNLIGHT INTO CHEMICAL ENERGY (ATP AND NADPH). THE DARK REACTIONS FIX CO 2 INTO SUGARS, USING THE ATP AND NADPH GENERATED BY THE DARK REACTIONS.

4. LIGHT HAS CHARACTERISTICS OF BOTH A PARTICLE AND A WAVE A WAVE IS CHARACTERIZED BY A WAVELENGTH AND A FREQUENCY c =

6. LIGHT IS ALSO A PARTICLE WHICH WE CALL A PHOTON  EACH PHOTON CONTAINS AN AMOUNT OF ENERGY CALLED A QUANTUM.  THE ENERGY CONTENT OF LIGHT IS NOT CONTINUOUS, BUT IS DELIVERED IN DISCREET PACKETS OR QUANTA.  E = h, where h is Planck’s constant

13. Bacteriochlorophyll a Chlorophyll a Phycoerythrobilin  -carotene Chlorophyll b

14. ENGELMANN EXPERIMENT (1881)

16. PHOTOSYNTHESIS TAKES PLACE IN COMPLEXES CONTAINING LIGHT- HARVESTING ANTENNAS AND PHOTOCHEMICAL REACTION CENTERS

18. EMERSON AND ARNOLD’S FLASHING LIGHT EXPERIMENTS WITH CHLORELLA (1932) 1. Gave brief flashes (10 -5 s) of light to Chlorella suspension and measured the amount of O 2 produced. (The flashes were spaced 0.1 s apart for maximum efficiency of dark reaction.) 2. Varied intensity (light energy) of flash and plotted the O 2 produced per flash versus the flash energy (number of photons).

19.  QUANTUM YIELD = 0.1

20. RED DROP EFFECT Carotenoid absorption: carotenoids have photoprotective effect

21. EMERSON ENHANCEMENT EFFECT

24. Stroma lamellae Double membrane Grana stack (thylakoids) Stroma

26. PSII PSI

27. Antenna complex as energy funnel

29. LHCII Antenna Complex ~15 LHCII PROTEIN

36. PSI

39. CHEMIOSMOTIC MECHANISM