Chlorophyll is the pigment used by plants to absorb energy in a process known as photosynthesis. Chlorophyll is a green pigment that is responsible for a plant's colors. When chlorophyll absorbs sunlight as energy, it begins a reaction to allow for the manufacture of sugar and other molecules.
Chlorophyll is in the thylakoid sacs of the chloroplast. Two types of chlorophyll, a and b, are found in plants. They combine in groups of hundreds to form a photosynthetic unit.. The two types of chlorophyll vary in color and chemical composition. Both are associated with specialized proteins that enter or span the membrane of the thylakoid sac.