photosynthesis notes for 1010th class by AIIMIIT

Photo=light
Synthesis=prepare

Process where plants use sunlight ,co2 and h20 to prepare glucose and liberate oxygen.

Raw materials needed for photosynthesis
Are
Co2
H20
Sunlight

Co2 + h20 •••••••> c6h12o6 + h2o + o2

Mains steps of photosynthesis are as fallows

1.plants trap sunlight
2.sunlight aplts water to protons ,oxygen gas and electrons(photolysis of water)
3.co2 is absorbed and converted to complex carbohydrates like glucose
4.glucose converted to starch and passed through poem to all parts of plant

Important points to be noted

oxygen during photosynthesis comes from h2o not co2 (remember)

Photosynthesis has mainly 2 steps

1.light reaction (occurs in sunlight)
2.dark reaction (occurs after sunlight
It does not mean in the dark)

1.light reaction

Plants trap sunlight
Chlorophyll a and b get excited
Liberates electrons
Electrons of chlor a passes through various electron acceptors
Like cytochrome,ferridoxin, etc
Due to energy difference ATP,NADP are prepared
Then that electron goes to chlo b and gets it to ground state
To get back chlo a to ground state
Water splits in presence of light
Into hydrogen ions,o2 gas ,and electrons
Electrons get back chlo a to ground state
O2 gas enters atmosphere
Hydrogen ions make NADP TO NADPH2
Now ATP and NADPH2 enters dark reaction

2.DARK REACTION

Co2 is absorbed by RUBP
(Ribulose 1 5 biphosphate)
PGA reacts with ATP and forms PGAL
PGAL reacts with NADPH2 to form glecreol dehyde 3 phosphate
After series of reaction
Glucose is formed
Converts to starch
Transported to all parts by phloem
It is called translocation