The plant's green pigment does not just provide color, it serves a vital function. Green plants efficiently use solar energy to make food. The food substance is in the form of sugars, starch, fat, protein and vitamins. The green pigment in plants, called chlorophyll, is what enables the plant to absorb the sun's rays or light energy, which is then converted to chemical energy.
Green plants use the energy from light, combined with water and carbon dioxide to make food, in a process called photosynthesis. The word photosynthesis actually means "putting together with light". Chlorophyll plays a vital roll in photosynthesis, as it absorbs the light energy needed for this process.
Unless a plant is exposed to light, it won't normally produce chlorophyll. Not all plants have chlorophyll, therefore not all plants have green stems or leaves. Chlorophyll is found in algae and in some bacteria. Plants that are kept from light are often yellow or white, instead of green. The mushroom is an example of a plant devoid of chlorophyll. As such, the mushroom has other ways of making its food.
Within a plant's cell, chlorophyll is located in membranes called thylakoids. Often the membranes are contained in minute cell bodies called chloroplasts. The chloroplasts located within a plant's leaves carry out the photosynthesis process. After the chlorophyll absorbs the light energy it is sent to the reaction centers within the thylakoids. It is there that the light is converted to chemical energy.
The chemical energy produced after light energy is absorbed by chlorophyll, then uses the carbon dioxide from the air to make food. The food substance is in the form of sugars, starch, fat, protein and vitamins.
The two most common forms of chlorophyll are chlorophyll a and chlorophyll b. They absorb the long wavelengths or red rays, and the short wavelengths or blue-violet rays. These two types of chlorophyll are less effective at absorbing the middle wavelengths or green rays. Some bacteria have a type of chlorophyll that is better at absorbing longer wavelengths or infrared rays. Infrared rays are beyond the visible spectrum of light.