Sample question on photosynthesis

Question :
Green plants synthesize their food through the process of photosynthesis. The chemical process of photosynthesis can be summarized as in the schematic diagram below.
a) State the meaning of photosynthesis based on the schematic diagram above.
b) Starting with water and carbon dioxide as the raw materials, describe how a green plant produces starch molecules.
ANSWER
a) A process where a green plant produces glucose which will undergo condensation to form starch from carbon dioxide and water in the presence of chlorophyll and sunlight.

b)During light reaction, chlorophyll captures light energy which excites the electrons of chlorophyll molecules to higher energy levels.
In the excited state, the electrons can leave the chlorophyll molecules.
Light energy is also used to split water molecules into hydrogen ion (H⁺) and hydroxyl ions (OH^-) (Photolysis of water).
The hydrogen ions (OH^-) then combine with the electrons released by chlorophyll to form hydrogen atom.
The energy from the excited electrons is used to form energy-rich molecules of ATP.
Hydroxyl ion loses an electron to form a hydroxyl group.
This electron is then received by chlorophyll.
The hydroxyl groups then combine to form water and oxygen gas.
During the dark reaction, the hydrogen atoms are used to fix carbon dioxide in a series of reactions catalysed by photosynthetic enzymes and caused the reduction of carbon dioxide into glucose.
The glucose monomers then undergo condensation to form starch which is temporarily stored as starch grains in the chloroplasts.