Cell Structure and Function

Biomembranes

Cell Respiration

Contacts

Concept 7: Chlorophyll

Chlorophyll molecules embedded in the thylakoid membrane absorb light energy. These molecules are the most important pigments for absorbing the light energy used in photosynthesis. A chlorophyll molecule has a hydrophobic "tail" that embeds the molecule into the thylakoid membrane. The "head" of a chlorophyll molecule is a ring called a porphyrin. The porphyrin ring of chlorophyll, which has a magnesium atom at its center, is the part of a chlorophyll molecule that absorbs light energy. Examine the illustration to view the chlorophyll molecule and to learn which wavelengths of light are absorbed by this pigment. Compare the absorption spectrum of chlorophyll with the action spectrum of photosynthesis that Engelmann found.