Photosynthesis Leaves are green because they contain small bodies in the cells called chloroplasts. The chloroplasts contain a green pigment called chlorophyll. This green material gives the leaf its colour. With the help of chlorophyll and energy from the sun, a leaf can change lifeless substances into food. This process is called photosynthesis. Plants need water (H2O) and carbon dioxide (CO2) to make food through the process of photosynthesis. The water is gathered by the plant's roots. Carbon dioxide is gathered from the air through the stomata.

Photosynthesis (continued) The leaf uses chlorophyll and sunlight to change the water and carbon dioxide into oxygen and glucose (sugar). This sugar is mixed with water and sent to other parts of the plant to be used by the plant as food. The oxygen is released into the air through the stomata. This is usually written as: Carbon + water Glucose + oxygen This is usually read as carbon dioxide plus water in the presence of light and chlorophyll produces oxygen and sugar glucose. Light Chlorophyll

Photosynthesis summary Chloroplast They contain a green pigment called chlorophyll. These are small structures that vary in number and size. LIGHT Chlorophyll The chlorophyll traps sunlight and uses this energy to drive the process of photosynthesis. Photosynthesis is the name of the chemical reaction that produces the plant’s food. Therefore, Chloroplasts are where a plant makes its own food.

Photosynthesis activity

+ + Photosynthesis FOOD (GLUCOSE) OXYGEN ENERGY WATER CARBON DIOXIDE We know that plants make their own food from sunlight. They are the producers in the food chain. This is done in the green parts of the plant, e.g. upper surface of the leaves. The reaction for this is: FOOD (GLUCOSE) OXYGEN + ENERGY WATER CARBON DIOXIDE + Made byphotosynthesis and stored as starch in leaves, roots, stems, etc. Taken in through holes in the leaves USEFUL! waste product exhaled Taken in through the roots With light and chlorophyll