In this topic we are learning to: z Outline the role of photosynthesis in controlling the flow of energy and cycling of matter through the Earth.
z Formulate a word equation for photosynthesis.
z Investigate the environmental factors that affect the rate of photosynthesis.
The Sun supplies energy to the Earth in the form of light. Plants can use this light energy directly to make their own food. The way plants make their food is called photosynthesis.
Organisms that can make their own food are called producers.
Reactants of Photosynthesis A reactant is anything that is needed for a chemical reaction to take place.
1. Carbon dioxide from the air enters the plant through small openings in the leaves called stomata.
2. Water from the soil enters through the plant’s roots.
3. Chlorophyll is the green pigment found in the chloroplast of plant cells. It absorbs light energy and changes it into chemical energy.
4. Sunlight is the energy absorbed by the leaves. Learn more about reactants and products in Chemical World 12.1
Sunlight
Products of Photosynthesis
A product is anything that is produced in a chemical reaction.
Oxygen
1. Glucose is the food made by the plant. It can be used to provide energy for the plant. Many plants store excess glucose in the form of starch.
Chlorophyll Glucose Water
2. Oxygen can be used to provide energy for the plant. It is released into the air through stomata. The oxygen released by photosynthesis is important as it then becomes available to all other plants and animals for respiration.
