Final answer:
Photosystems, vital for the process of photosynthesis, are located in the thylakoid membranes of chloroplasts and consist of a light-harvesting complex and a reaction center which contain chlorophyll and carotenoid pigments.
Step-by-step explanation:
The photosystems, or light collecting units of photosynthesis, are found in the thylakoid membranes of chloroplasts. These important complexes, known as photosystem II (PSII) and photosystem I (PSI), are composed of a light-harvesting complex with antenna proteins, and a reaction center. The antenna proteins contain a mixture of chlorophyll a and b molecules and carotenoid pigments, which absorb light and transfer the energy to the reaction center. Chlorophyll absorbs light primarily in the violet, blue, and red wavelengths and reflects green, which is why plants appear green to us. Carotenoids absorb in the violet-blue-green range and reflect yellow-to-orange hues. The energy captured by these pigments is then used to initiate the conversion of light energy into chemical energy during the photosynthetic process.