A cell should be bounded by a membrane that make it as a single unit 

this membrane is called " cell membrane - plasma membrane 

It is composed mainly of phospholipid bilayer,  protein, cholesterol and glucose. 

How there is a bilayer of phospholipid ? 

Types and role of protein in the membrane  ?

Glucose which bind to protein and lipid forming glycoprotein and glycolipid which is " Glycocalyx "

Whta is the function of glycocalyx ? 

Role of glycocalyx in organ transplant  ?

Membrane is  semipermeable: how molecules can pass across it ?  

Passive vs active transport : which one uses energy and which one is against or with the concentration gradient  ?

Effect of hyper,  hypo and isotonic solutions on RBCs ? 

How cell can communicate with other near and far cells ?