Are chemistry of all living things the same or different?

"Chemistry" can mean anything. All living things are based on carbon, but that does not mean they have to resemble each other much. For instance, everything that has hands or feet uses the same five digit design, even if they don't have five digits. That just happens to be the way carbon and calcium work together. Everything that divides the hoof and chews a cud (cows) is good for food, but animals that divide the hoof and do not chew a cud (pigs), or chew a cud but don't divide the hoof (rabbits), are not good for human food. Carbon is the only element with bond strength to hold large molecules together, but the number of possible chemical combinations goes far beyond human understanding.