Photosynthesis
Made of
Combination of Carbon dioxide with water to form Carbohydrate
Can find almost everywhere
Can be found in large amount
Non-toxic
stable and contain little chemical energy.
Process
Abundant and cheap
Carbon of carbon dioxide is reduced and energy is supplied to it converting it to carbohydrate.
Carbon atom is at +4 oxidation state whereas whereas carbon atoms in carbohydrate are, in general at +0.
4 electrons must be found and placed into new bonding orbitals around the carbon atom to reduce it.
Carbon is more stable in the oxidized state thsn in the reduced state
Carbohydrate such as wood and sugar can burn, rekeasing energy but carbon dioxide does not.
Source
Light and Water
Light Dependent Reaction(Thykloid Reaction)
Light -Independent Reaction (Storma Reaction)
provides source of electrons
generates ATP and ADP
converts light energy to chemical
absorbs solar energy
Occurs in thylakoid membrane
3-phosphoglyceraldehyde can be taken out of the chloroplast and
used by the cell to build sugars, fats, amino acids, nucleic acids.
rest of the PGAL are coverted to RuBP
carbon is now both reduced and energized
Results in a chemiosmotic gradient
diphosphoglycerate is reduced by NADPH to 3-phosphoglyceraldehyde
First step- carboxylation
Takes place in Storma
ATP donates a highenergy
phosphate group to the 3-phosphoglycerate, conveting it to 1, 3-diphosphoglycerate
Nature of pigment
nature of light
chlorophyl b
chlrorophyll a
Photosystem II
Photosystem I
works together
accessory pigment
transfers electrons from water to NADPH. The electron’s energy is boosted twice, once at P680 and again at P700.
ATP Synthesises
cyclic electron transport
non-cyclic electron transport
permits production of extra ATP without synthesis of NADPH or production of free oxygen.
results in production of both ATP and NADPH, but the amount of ATP is not sufficient for the stroma reactions.