1. PHOTOSYNTESIS Dr. Mahesha H B Associate Professor and Head
Department of Sericulture
Yuvaraja’s College
University of Mysore, Mysuru, India
10 November 2018 1

2. PHOTOSYNTHESIS
The process in green plants and certain other organisms by which carbohydrates are synthesized from carbon dioxide and water using light as an energy source. Or
The synthesis of complex organic material using carbon dioxide, water, inorganic salts and light energy (from sunlight) captured by light-absorbing pigments such as chlorophyll and other accessory pigments.
10 November 2018

3. According to Biological Economists ALL WEAALTH ORIGINATES
6 CO ATP + 12 H2O + 12 NADPH+ / 2 H+
C6H12O6+ 18 Pi + 18 ADP + 12 NADP+ + 6(O2)
According to Biological Economists
ALL WEAALTH ORIGINATES
DIRECTLY OR INDIRECTLY
AS A CONSEQUENCE OF PHOTOSYNTHESIS
10 November 2018

4. Photosynthesis is the biggest photochemical & biochemical phenomena acting as a master key for the existance of life on this globe. Inturn solar energy is the chief driver of this reaction
10 November 2018

5. Nature of radiant energy
10 November 2018

6. ELECTROMAGNETIC SPECTRUM OF SUN LIGHT
nm induces sensation in photosynthesis
10 November 2018

7. Photochemical Changes in Chlorophyll
A. Loss as heat.
B. Loss of light.
C. Resonance energy transfer.
D. Energy transduction
10 November 2018

8. Photochemical Changes in Chlorophyll
10 November 2018

9. Photosynthetic pigments
Chlorophyll a, b, c, d, e, bacteriochlorophyll
Carotenoids – β carotene
Xanthophylls
Phycobilins - Phycocyanin
Phycoerythrin
10 November 2018

10. Absorption Spectra of Photosynthetic pigments
10 November 2018

11. Site of Photosynthesis
The light reactions of photosynthesis, are associated with the thylakoid membranes.
In contrast, the light-independent reactions, or so-called dark reactions, notably CO2 fixation, are located in the stroma.
10 November 2018

12. PHOTOSYNTHETIC UNIT AND PHOTOCHEMICAL REACTION CENTRE
10 November 2018

13. Steps/out line of Photosynthesis
Light Reactions of Photosynthesis converts solar energy into potential energy. The light reaction converts ADP and NADP+ into the ATP and NADPH and produces oxygen.
Cyclic Phosphorylation:
Non-cyclic Phosphorylation:
Calvin Benison Cycle of Photosynthesis The light independent reactions fixes CO2 in to C6H12O6 using the products of light reaction
10 November 2018

14. Photosystems
The photochemical phase requires the interaction of 2 photosystems.
Photosystem I: consists ~200 light harvesting chlorophylls,
~50 Carotenoids, a mol. of P700, 1 mol. of an unidentified compound (X), one cytochrome f, one plastocyanin, two cytochrome b 563, Ferredoxin reducing substance and 1/2 membrane bound ferredoxin molecule.
It produces a strong reductant which reduces NADP+ to NADPH2+.
Photosystem II: consists~200 light harvesting chlorophylls,
~50 Carotenoids, a trapping chlorophyll mol. of P680,
one mol. of an unidentified compound (Z), a plastoquinone, ~4 plastoquinone equivalents, 3 mn mole., two cytochrome b 559 and chloride.
The system is concerned with the release of O2.
In association both I & II produces, ATP and NADPH.
10 November 2018

15. Mechanism of Light Reaction
Photophoshoriyation: The synthesis of ATP from ADP and phosphate that occurs in a plant using radiant energy absorbed during photosynthesis:
ADP + pi ATP
Photolysis of Water:
4H2O --->4H+ + 4OH-
4OH- 2H2O2  2H2O + O2
10 November 2018

16. Cyclic Photophosphorylation
Redox potential:
The tendency to
release and acceptance of electrons.
Expressed in volts/milivolts.
The term Redox has been derived from
Reduction-Oxidation.
10 November 2018

17. Non cyclic photophosphorylation
10 November 2018

18. Non cyclic photophosphorylationX Q
4H2O --->4H+ + 4OH-
4OH- 2H2O2  2H2O + O2
10 November 2018

19. Dark reaction/C3 cycle/Calvin Benson reaction/ Blackman reaction
10 November 2018

20. Reaction steps of C3 cycle
10 November 2018

21. Out line of C3 cycle reactions
Glyceric acid 3 Phosphate
1,3 bisphosphoglyceric
acid
3 phosphoglyceric
acid
Fructose 1,6 bis
phosphate
Ribulose 1,5 bisphosphate
Ribose
5 Phosphate
Dihydroxy acetone p
Ribulose
5 Phosphate
Fructose 6 Phosphate
Erythrose 4 Phosphate
Sedoheptulose
7 Phosphate
Sedoheptulose
1,7 bisphosphate
Xylulose
5 Phosphate
Glucose 6 Phosphate
10 November 2018

22. Out line of C3 cycle reactions
10 November 2018

23. THE OVERALL REACTION OF PHOTOSYNTHESIS
6 CO ATP + 12 H2O + 12 NADPH+ / 2 H+
C6H12O6+ 18 Pi + 18 ADP + 12 NADP+ +6O2
10 November 2018

24. C 3 Plants
A plant that utilizes the C3 carbon fixation pathway as the sole mechanism to convert CO2 into an organic compound(i.e. 3-phosphogylycerate).
10 November 2018

25. C 4 Plants
A plant that utilizes the C4 carbon fixation pathway in which the CO2 is first bound to a phosphoenolpyruvate in mesophyll cell resulting in the formation of four-carbon compound (oxaloacetate) that is shuttled to the bundle sheeth cell where it will be decarboxylated to liberate the CO2 to be utilized in the C3 pathway.
10 November 2018

26. Kranz Anatomy
10 November 2018

27. 10 November 2018

28. Oxaloacetate Aspartate Aspartate Tansaminase Tansaminase
10 November 2018

29. Photorespiration The process by which in the presence of light plant consumes oxygen and releases carbon dioxide (in stead of fixing (CO2) during Photosynthesis, resulting in a decrease in Photosynthetic output.
10 November 2018

30. Photorespiration Pathway
Glycine
Glyoxolate
Glycolate
Serine
Phosphoglycolate
Hydroxypyruvate
10 November 2018

31. Photorespiration Pathway
Rubisco
Kinase
α-OH
reductase
Catalase
Oxidase
> H2O+O
Transamination
Released in
photorespiration
10 November 2018

32. Acknowledgements to INTERNET FOR PICTURES AND PHOTOGRAPHS
10 November 2018