How does photosynethesis work? This clip - from an animation, produced by BioMEDIA Associates - explains the biology of plants.
By way of further explanation ... as people have pores (on their skin) leaves have pores (called "stomata"). Carbon dioxide - which plants need to live - is able to enter a leaf through its stomata.
Once inside the leaf, carbon dioxide is able to reach the leaf's chloroplasts. The chloroplasts contain a substance called chlorophyll.
Sunlight is important when plants make their own food during photosynethesis. Light from the sun is the energy which chlorophyll needs to bind carbon dioxide to the water which a plant gets through its roots.
When carbon dioxide and water combine, inside the plant, two new products - a carbohydrate called "glucose" plus oxygen - are formed. The plant needs one of the products but does not need the other:
1. The plant uses glucose;
2. The plant discards oxygen (through its leaves).
When a plant discards oxygen through its leaves, that process is called "transpiration."
Transpiration is the reason why the world's biggest rainforests are sometimes called the "lungs of the world." All those leaves, on all those trees, are releasing oxygen into the surrounding environment.
Plants are the only living organisms in the world which can make their own food through this process of photosynethesis.
There is something else to know about the biology of plants. Just like people and animals, plants take in oxygen and release carbon dioxide in a process called "respiration." How respiration works in plants is described in this animation.
To deepen your understanding of photosynthesis, review these "exam skill" problems.
To test your knowledge of photosynthesis, take a practice exam.
Clip from "The Biology of Plants," by BioMEDIA Associates. Copyright, BioMEDIA Associates, 1997, all rights reserved. Clip provided here as fair use for educational purposes.