* Cell membrane: This is a thin, flexible barrier that surrounds all cells. It is primarily made of phospholipids and proteins. The membrane's main role is to regulate what enters and exits the cell, maintaining the cell's internal environment. It is selectively permeable, allowing some substances to pass through while blocking others.
* Cell wall: This is a rigid, outermost layer found in plant cells, bacteria, fungi, and some protists. It is primarily made of cellulose, chitin, or peptidoglycan. The cell wall provides structural support and protection, helping to maintain the cell's shape and resist pressure changes. It also plays a role in filtering substances entering the cell.
In short, the cell membrane is a dynamic barrier that controls the movement of molecules, while the cell wall is a structural component that provides strength and protection.
