Biology-Photsynthesis

Plants are made of organs like stems, roots and leaves. These organs are made up of tissues:

• Mesophyll- most of photosynthesis in a plant occurs here
• Xylem and Phloem- transport substances (water,mineral ions and sucrose) around the plant
• Epidermal- covers the whole plant

Carbon Dioxide + Water ----LIGHT ENERGY----> Glucose + Oxygen

Photosynthesis produces 'food' for plants and algae. The 'food' is glucose.

Photosynthesis happens inside the chloroplasts.

Chloroplasts contains a green substance called Chlorophyll- this absorbs sunlight and uses its energy to convert carbon dioxide and water into glucose. Oxygen is produced as a by-product.

Photosynthesis happens in the leaves of all green plants.

Limiting factors of rate of photosynthesis: (can be further affected by enviromental conditions)

• Temperature
• Light Intensity
• CO2

LACK OF LIGHT
Light provides energy needed for photosynthesis. When light is increased, the rate of photosynthesis increases untill it stops at a certain point as light no longer effects the plant.

LACK OF CARBON DIOXIDE
CO2 is a raw material needed in photosynthesis. The rate of photosynthesis will only increase up to a certain point as it no longer becomes a limiting factor.

TEMPERTAURE
Too low- enzymes needed for photosynthesis work slowly or Too high- enzymes needed for photosynthesis and its other reactions will be damaged.

1) FOR RESPIRATION

• Plants make glucose in leaves and use some for respiration-releases energy to convert rest of the glucose into useful substances, which can be used to build new cells and grow.

2) MAKING CELL WALLS

• Glucose is converted into cellulose for making strong cell walls.

3) MAKING PROTEINS

• Glucose is combined with nitrate ions to make amino acids which are then made into proteins

4) STORED IN SEEDS

•  Glucose is turned into lipids for storing in seeds.

5) STORED AS STARCH

Glucose is turned into starch and stored in roots, stems. leaves ready for use.