Derek Stevenson, age 10, of St. Catharines) Ontario, Canada, for his question:
What exactly is chlorophyll?
Chlorophyll colors our summer lawns and grassy meadows. It adds special tints of blue green or gray green, golden green or green green to each of the different plants. It works with the beaming sun to create basic food for the plant world and the plant world feeds the animal world. Chlorophyll also provides the breathable oxygen for all the plants and animals.
Ecology explains how all the plants and animals in a neighborhood depend upon each other to keep going. However, all of them also need a few global supplies, such as water, breathable air and a certain amount of warm sunshine. The earth provides the air; chlorophyll makes it breathable. The sun provides the warmth; chlorophyll uses its energy to feed all living things upon the earth.
The study of chlorophyll takes us down to the miniworld of atoms, molecules and busy little bodies too small for our eyes to see. The place to look for it is inside any green leaf. For chlorophyll is the gorgeous greenery of the thriving plant world.
Its busy little bodies are called chloroplasts, and it takes about 100 of these little flat disks to measure an inch. Inside the plant cells they crowd in jellified cytoplasm, and the chlorophyll extracted from a leaf is a green liquid. Each cell contains one or more chloroplasts. But scientists estimate that in the teeming cells of an average elm leaf there may be 1 billion of these busy little green bodies.
Through the daylight hours, chlorophyll uses energy from sunlight to convert water and gaseous carbon dioxide into basic sugary plant food. This miraculous sunshine recipe is called photosynthesis and until quite recently nobody really knew the secrets of this magic recipe, though everyone knew that it provides oxygen and basic plant food on a global scale.
The plants use dissolved chemicals from the soil, plus sugar produced by chlorophyll, to create the thousands of different substances they need to grow and multiply. Most animals feed on plant food, and meat eating animals dine on the plant eaters.
Photosynthesis uses up the waste carbon dioxide that all living things breathe out. During the complicated sugar¬ making recipe, it gives off oxygen as a waste product. On a sunlit day, the forests pour countless tons of breathable oxygen into the air and the breezes waft it around and around the globe.
Chlorophyll molecules are packages of atoms of carbon and hydrogen, nitrogen, oxygen and magnesium. They are similar to the molecules that color our red blood cells. In many ways they are quite different. But both chlorophyll and red blood perform chemical switches with oxygen and carbon dioxide.