What is photosynthesis? Plants do not need to depend on people or animals for food. Many plants are able to make their own food. The process by which plants make their own food is called photosynthesis.
The word photosynthesis is a combination of two words.
“Photo” means light. “Synthesis” is putting together.
In this lesson we are going to learn about how plants make food by using light and what sort of things are put together in order to do this process.
Green plants make their own food from carbon dioxide and water in the presence of chlorophyll using the energy of sunlight. This process is called photosynthesis.
Photosynthesis takes place in the leaves of a plant.
During photosynthesis light energy turns into chemical energy.
1) Carbon dioxide
What is chlorophyll?
Chlorophyll is a green chemical that gives plants their green colour.
How is carbon dioxide collected by plants for photosynthesis?
There are tiny microscopic pores (holes) in the leaves which we call ‘stomata’. Carbon dioxide from the air passes through these small pores, so that leaves can have carbon dioxide which they need in the process of photosynthesis.
How is water collected by plants for photosynthesis?
Water is absorbed by the roots and passes through the stem on its way to the leaves.
How is sunlight collected by plants for photosynthesis?
Sunlight is absorbed by the green chemical, chlorophyll in the leaves.
Glucose produced in photosynthesis
Glucose (C6H12O6) is the food that plants make for their own consumption. It is made up of carbon, hydrogen and oxygen atoms during the process of photosynthesis.
How do plants use glucose produced during the process of photosynthesis?
1. Glucose is converted into chemicals required for growth of plant cells.
2. Glucose is also converted into starch that can be converted back to glucose when the plant requires it.
3. Glucose is broken down during the process of respiration.
Oxygen produced in photosynthesis
Oxygen is produced as a by-product during the process of photosynthesis. This oxygen is very important for all animals to breathe in and stay alive on the Earth.