- Energy that can travel through empty space in the form of waves, light is a form of this. The differences lie in the wavelengths. Each wavelength corresponds to a certain amount of energy. The wavelength is the distance between consecutive wave peaks. Sunlight contains all of the wavelengths of visible light.
- Pigments- a substance that absorbs certain wavelengths ( colors) of light & commonly reflects all of the others. It makes the human eye sensitive to light. In plants, light energy is harvested by pigments that are located in the thylakoid membrane of chloroplasts.
- Chlorophyll is a green pigment in chloroplasts that absorbs light energy to start photosynthesis. It absorbs mostly blue & red light & reflects green & yellow light which makes plants appear green. there are two types of chlorophyll; chlorophyll a & chlorophyll b. carotenoids,pigments also found in plants, absorb blue & green and they reflect yellow, orange, & red. carotenoids aid photosynthesis by allowing plants to absorb additional light energy. chlorophyll fades in fall then carotenoids appear.
- when light hits a thylakoid, energy is absorbed by many pigment molecules. they all funnel the energy to a special chlorophyll molecule in a region called the reaction center,
where the energy causes the electrons to become "excited" & to move to a higher energy level. These electrons are transferred quickly to other nearby molecules & then to an electron carrier.