A stable subatomic particle occurring in all atomic nuclei, with a positive electric charge equal in magnitude to that of an electron, but of opposite sign
A subatomic particle of about the same mass as a proton but without an electric charge, present in all atomic nuclei except those of ordinary hydrogen
The semipermeable membrane surrounding the cytoplasm of a cell
A dense organelle present in most eukaryotic cells, typically a single rounded structure bounded by a double membrane, containing the genetic material