When you have finished this page, try the Photosynthesis Quiz.

Photosynthesis is the making of food by plants. The essential ingredients in making this food are sunlight, the chlorophyll that is present in green plants, water and carbon dioxide in the air. Photosynthesis is necessary not just for plants to make food for themselves, but for animals, including us eventually.

How does photosynthesis occur?

Water is taken in through the roots of the plant and transported to the leaves by the xylem (tubes that carry water) in the stems.

Carbon dioxide animals breathe out from the air goes into the leaves through the tiny pores called stomata and is spreads to the cells that contain chlorophyll in the inside layer of the leaf.

Sunlight is used to break down the water in the plant into oxygen which the plant gives off and we use to breathe. The hydrogen is then used with the carbon dioxide to create the food for the plants and ultimately food for animals as well.


Plants and animals are both kingdoms of living things. They differ in important aspects. The chart below summarizes some of these differences.

Plants generally are rooted in one place an do not move on their ownMost animals have the ability to move fairly freely.
Plants contain chlorophyl and can make their own foodAnimals cannot make their own food and are dependent on plants and other animals for food. 
Plants give off oxygen and take in carbon dioxide given off by animals.Animals give off carbon dioxide which plants need to make food and take in oxygen which they need to breathe.
Plants cells have cell walls and other structures differ from those of animals.Animal cells do not have cell walls and have different structures than plant cells
Plants have either no or very basic ability to sense.Animals have a much more highly develped sensory and nervous system.