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.