plasma membrane is also called cell membrane. the outer most layer in animals cell and in plants next to the cell wall.this membrane is elastic,delicate,and thin. it is composed of lipid,and proteins. it is a semi permiable layer. it means that cell membrane has the small pores, for passing small substances like ATP energy and many more.it seprate the organelles from the external enviroment. so due to small pores in cell membrane the information is passed from cell membrane. i hope it will help you fraind.