Photosynthesis
A Quick Breakdown
What is Photosynthesis?
Photosynthesis is the process by which plants make their own food.
"photo" which means light
"synthesis" which means putting together
Plants need food but they do not have to wait on people or animals to provide for them. Most plants are able to make their own food whenever they need it. This is done using light and the process is called photosynthesis.
To make food, plants need:
- Water
- Sunlight
Let’s take a look at how these are collected by plants.
- Carbon dioxide from the air passes through small pores (holes) in the leaves. These pores are called stomata.
- Water is absorbed by the roots and passes through vessels in the stem on its way to the leaves.
- Sunlight is absorbed by a green chemical in the leaves.
The Process of Photosynthesis
Photosynthesis takes place in the leaves of plants. The leaves are made up of very small cells. Inside these cells are tiny structures called chloroplasts. Each chloroplast contains a green chemical called chlorophyll which gives leaves their green color.
- Chlorophyll absorbs the sun’s energy.
- It is this energy that is used to split water molecules into hydrogen and oxygen.
- Oxygen is released from the leaves into the atmosphere.
- Hydrogen and carbon dioxide are used to form glucose or food for plants.
Some of the glucose is used to provide energy for the growth and development of plants while the rest is stored in leaves, roots or fruits for later use by plants.
Here is the process in greater detail:
Light dependent Reactions
Light dependent reactions occur in the thylakoid membrane of the chloroplasts and take place only when light is available. During these reactions light energy is converted to chemical energy. The Calvin Cycle The Calvin Cycle reactions occur in the stroma of the chloroplasts. Although these reactions can take place without light, the process requires ATP and NADPH which were created using light in the first stage. Carbon dioxide and energy from ATP along with NADPH are used to form glucose.
This information can be written in a word equation as shown.
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Photosynthesis Poster
This will give you a quick, easy guide, to remembering the basic steps involved.