Question

if we inject chlorophyll in human body does it do the process of photosynthesis

Answer 1

There are a few photosynthetic animals, such as corals and convoluta worms and the Elysia chlorotica sea slug, but these creatures capture whole algae (or just their chloroplasts in the case of the sea slug) because chlorophyll by itself is extremely dangerous and toxic to animals. This is because chlorophyll is very efficient at absorbing light energy and transferring that energy to other molecules. If the chlorophyll is not contained within a photosystem protein complex (and even sometimes when it is), that light energy will be transfered to oxygen molecules to produce dangerous free radicles that will subsequently oxidize DNA, proteins, lipids, or pretty much anything else inside a cell.Injecting chlorophyll into your skin would make you get a really nasty sunburn from any light source (even indoor lighting). Fortunately, animals evolved to avoid absorbing chlorophyll from our food, so you can safely eat green vegetables.