Presentation2

oxygenic and non oxygenic photosynthesis

1. OXYGENIC AND NON-OXYGENIC PHOTOSYNTHESIS

2. GROUP MEMBERS Zainab Akram (25) Saima Afridi (59) Maria Younas (61) Faiza Aslam (55) Sidra Shahzadi (53)

3. Introduction of photosynthesis Photo means light and synthesis means to put together T he process by which radiant energy(light) is converted into chemical energy by autotrophic organism Energy poor inorganic oxidized componds of C and H are reduced to energy rich carbohydrates and oxygen is released

4. Discovery of photosynthesis Van helmont’s experiment (1643) Priestley’s experiment (1771) Ingenhousz’s experiment (1779)

5. Evolution of photosynthesis Reducing environment changed to oxidizing environment – oxygenic photosynthesis evolve

6. IMPORTANCE OF PHOTOSYNTHESIS Plant metabolism Energy production Food chain Composition of air

7. Site of photosynthesis - choloroplast Location in mesophyll cells of leaf Structure double membrane bounded organelle having thylakoids and grana Size 2- 10 μ m

8. Photosynthetic pigments Pigments captures light energy for photosynthesis I n plants Carotenes(orange) Xanthophyll(yellow) Phaephytin -a(gray brown) Phaephytin -b(yellow brown) Cholophyll –a(blue green)

9. Cholorophyll –b (yellow green) In cyanobacteria( phycobilliprotein ) In algae( cholorophyll )

10. OXYGENIC PHOTOSYNTHESIS

11. LIGHT REACTION Light reaction are light dependent reaction which use light directlly Formation of ATP AND NADPH NADPH provides energized electron while ATP provides chemical energy for the synthesis of sugar

12. COMPONENTS OF LIGHT REX . Photosystem -I (p700) Photosystem –II (p680) Antenna complex Reaction centre ( cholorophyll a molecules , primary electron acceptor, electron carrier of electron system)

13. Non –cyclic phosphorylation Exciation of electron in PS-II Photolysis Electron transport chain(ETC) ATP synthesis Excitation of electron in PS-I NADPH reduction

14. CYCLIC PHOSPHORYLATION Also called short circuit cycle NADPH level rise ATP level rise No oxygen will release

15. chemiosmosis Mechanism of ATP synthesis(cyclic + non-cyclic) Uses membranes for coupling redox rex . Diffusion of H+ Energy of electron makes ATP

16. NON –OXYGENIC PHOTOSYNTHESIS

17. PURPLE SULPHUR BACTERIA Scientific name- Chromatiales Rank- order Two families (i) Chromatiaceae (internal sulfur globules) (ii) ecthiorhodospiracea (external sulfur globules)

18. INTRODUCTION Group of proteobacteria (phylum of gram negative bacteria) Anaerobic or microaerophillic Lives in hot springs Favourable place is meromictic lakes (which are permanently stratified having denser saline water at bottom and less dense fresh water at surface)

19. Formation of blooms . If sufficient sulfate is present to support sulfate reduction, the sulfide, produced in the sediments, diffuses upward into the anoxic bottom waters, where purple sulfur bacteria can form dense cell masses, called blooms, usually in association with green phototrophic bacteria

20. Chemical equation

21. Light Rex. In PURPLE SULFUR BACTERIA Source of electron P.S.B and P.N.S.B Electro –ve and electro +ve reduction potential Source of light Location of reaction

22. Why we need this cyclic flow of electrons in light reaction?

23. Conti…. Photoreactive centers Photopigments or light harvesting molecule Types of electron carrier embedded electron carrier mobile electron carrier

24. GREEN SULFUR BACTERIA ( Chlorobiaceae )

25. INTRODUCTION Anaerobic, anoxygenic , photoautotrophic photosynthetic bacteria All species are non-motile Cells of different species are spherical, curved, rods or ovoid Can survive in extreme conditions Found in deep oceans use sulfide or sulfur as a source of reduction for photosynthesis Sulfur produced from sulfide, but never inside the cell

26. Photosynthesis in Green Bacteria Reaction Centre: they use type-1 reaction centre P840 as it absorbs the light of 840nm. Electron Acceptor: Electron acceptor molecules resides at about 0.0 reduction potenial in purple bacteria while in green bacteria they are at -0.6 reduction potential that is much more than NADH. This is the reason that NADH is reduced in green bacteria but not in purple sulfur bacteria

27. Chemical equation 6CO2 + 12H2S C6H12O6 + 12S + 6H2O + energy Light

28. Mechanism of Light R ex. In Green sulfur bacteria