The document discusses photosynthesis and purple sulfur bacteria. It explains that photosynthesis converts light energy to chemical energy by reducing carbon and hydrogen compounds and releasing oxygen. It describes the structures and pigments involved in photosynthesis, including the two photosystems that generate ATP and NADPH. Purple sulfur bacteria are anaerobic bacteria that use sulfide or sulfur instead of water as an electron donor for photosynthesis. They are found in places like hot springs and produce sulfur globules inside or outside the cell.
4. Photo means light and synthesis means to
put together
The 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
9. Location
in mesophyll cells of leaf
Structure
double membrane bounded organelle
having thylakoids and grana
Size
2- 10μm
10. Pigments captures light energy for
photosynthesis
In plants
Carotenes(orange)
Xanthophyll(yellow)
Phaephytin-a(gray brown)
Phaephytin-b(yellow brown)
Cholophyll –a(blue green)
11. Cholorophyll –b (yellow green)
In cyanobacteria(phycobilliprotein)
In algae(cholorophyll)
12.
13. 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
14.
15. Photosystem -I (p700)
Photosystem –II (p680)
Antenna complex
Reaction centre (cholorophyll a molecules ,
primary electron acceptor, electron carrier of
electron system)
16. Exciation of electron in PS-II
Photolysis
Electron transport chain(ETC)
ATP synthesis
Excitation of electron in PS-I
NADPH reduction
17.
18. Also called short circuit cycle
NADPH level rise
ATP level rise
No oxygen will release
19.
20. Mechanism of ATP synthesis(cyclic + non-
cyclic)
Uses membranes for coupling redox rex.
Diffusion of H+
Energy of electron makes ATP
21.
22.
23.
24.
25.
26.
27.
28. Scientific name- Chromatiales
Rank- order
Two families
(i) Chromatiaceae(internal sulfur globules)
(ii) ecthiorhodospiracea(external sulfur
globules)
29.
30. 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)
31. . 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
32.
33. Source of electron
P.S.B and P.N.S.B
Electro –ve and electro +ve reduction
potential
Source of light
Location of reaction
34. Why we need this cyclic flow
of electrons in light reaction?
35. Photoreactive centers
Photopigments or light harvesting molecule
Types of electron carrier
embedded electron carrier
mobile electron carrier
36.
37.
38.
39. 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
40. 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