EducatorSharmin

Cell membranes & Transport  Biology The cytoplasm is surrounded externally by a  cell surface membrane , also called the  plasma membrane . It is a  partilly permeable membrane  which controls subtances entering or leaving the cell. Similar membranes may also surround large spaces or vacuoles within the cell.  In a plant, there is a  cell wall  which encloses the whole cell. This cell wall is made of  cellulose . It protects the cell from injury.  Learning Outcomes: You should be able to: a. Describe the structure of cell membranes b. Explain the functions of the molecules that make up cell membranes c. Explain how substances enter and leave cells d. Find the water potential of plant tissues through experiment Q.1. What is phospholipids? Ans: A substance whose molecules are made up of a glycerol molecule , two fatty acids and a phosphate group; a bilayer of phospholipids forms the basic structure of all cell membranes. Fluid mosai...