How does a pigment capture the suns energy?
When a photon hits a pigment, it excites the electrons in one of the double bonds in the pigment. In chlorophylls, these double bonds are the ones that are found closest to the magnesium atom at the centre of the pigment. When one of these electrons is excited by just the right wavelength, i.e. just the right energy of light, it will leave the pigment and evetually enter a series of proteins located on the thylakoid membranes collective known as the photosynthetic electron transport chain. This electron transport chain functions similarly to its animal analog in that it involves a series of redox reactions that use the energy in the electron to pump protons across the thylakoid membrane. This creates a proton concentration gradient across the membrane and ATP synthase can harvest the energy of protons moving down the gradient to make ATPs. This is a brief explanation of how light energy is converted by plants to ATPs.
