Revision: Science >> Getting to Know Plants Science Secondary School (English Medium) (5 to 8) Class 6 CBSE

Photosynthesis: The process by which plant leaf prepares or synthesizes food from water and carbon dioxide in the presence of chlorophyll and sunlight is called photosynthesis.

Venation: Arrangement of a pattern of veins in a lamina is called venation.

Tranpiration: This is the process by which there is a loss of water in the form of vapour by evaporation from the surface of leaves. It has a cooling effect, it causes the suction force to make roots absorb more water with mineral ions.

Releasing electrons and dividing the water molecule (H2O) into its two components (Hydrogen and Oxygen). Photolysis is the term used to describe this reaction, which is characterised by the fracturing of molecules by light (photo = light, lysis = breaking).

Photosynthesis is the process by which living plant cells, containing chlorophyll, produce food substances (glucose and starch) from carbon dioxide and water by using light energy. Plants release oxygen as a byproduct during photosynthesis.

In the presence of chlorophyll, photosynthesis is the process by which green plants and certain other organisms convert carbon dioxide and water into glucose (a form of sugar) using light energy, typically from the sun. As a byproduct, this process generates oxygen.

The balanced chemical equation is: \[6\mathrm{CO}_{2}+12\mathrm{H}_{2}\mathrm{O}\frac{\text{light energy}}{\text{chlorophyll}}\mathrm{C}_{6}\mathrm{H}_{12}\mathrm{O}_{6}+6\mathrm{H}_{2}\mathrm{O}+6\mathrm{O}_{2}\uparrow\]

1. Photosynthesis mainly occurs in mesophyll cells (palisade and spongy) of leaves, using chlorophyll to trap sunlight.
2. Carbon dioxide enters the leaf via stomata by diffusion down a concentration gradient.
3. Water is absorbed by roots, transported via the stem to mesophyll cells of the leaves.
4. Using light energy, chlorophyll helps synthesize glucose (C₆H₁₂O₆) from CO₂ and H₂O, releasing O₂ as a by-product.
5. The balanced chemical equation is: \[6\mathrm{CO}_{2}+12\mathrm{H}_{2}\mathrm{O}\frac{\text{light energy}}{\text{chlorophyll}}\mathrm{C}_{6}\mathrm{H}_{12}\mathrm{O}_{6}+6\mathrm{H}_{2}\mathrm{O}+6\mathrm{O}_{2}\uparrow\]