Cell wall and cell membrane both are constituents of a cell. The main difference between cell wall and cell membrane is, cell membrane is present in all cells but cell wall is only present in plants, bacteria, fungi and algae. It is not present in the Protozoa and animal cell. Cell wall covers the cell membrane, which is a partially permeable membrane.
What is Cell Wall?
Cell wall basically provides rigidity and strength to the cell and it protects the cell against all forces, acting on it externally. Cell wall only prevents the entry of very large molecules into the cell. It also maintains a good water balance in the cell and this creates an appreciable osmotic environment. The structures of cell wall differs in prokaryotic and eukaryotic cell. In a prokaryotic cell it is made up of peptidoglygans, lipoprotein and lipopolysaccharides. It a eukaryotic cell it is made up of cellulose, polysaccharides and lignin.
What is Cell Membrane?
Cell membrane is covered by the cell wall. It works as a barrier for the cell. It separates the internal environment from the external environment. It functions in providing shape to the cell, to make it stable, to give strength to the cytoskeleton and in the formation of tissues. Protein receptors are also present in a cell membrane and they basically function in receiving signals from the other cells. It’s structure consist of lipids, proteins and carbohydrates. There types of proteins and two types of sugar is found in the cell membrane. Moreover, the carbohydrate present in the cell membrane is known as glycoprotein. It is not that elastic and it allows the passage of very big molecules to pass through.
Key Differences between Cell Wall and Cell Membrane
- Cell membrane is also known as plasma membrane or plasma lemma, cell wall is not.
- Cell membrane is found in animal cells and cell wall in plant cells.
- Cell wall covers the cell membrane and forms the outer covering.
- Cell membrane is partially permeable but cell wall is completely permeable.
- Cell membrane do not contain cellulose, cell wall does.
- Cell wall is elastic, cell membrane is not.
- Cell wall controls turgidity of a cell, plasma membrane does not.
- Cell wall made up of peptidoglygan is present in a bacteria.
- Cell wall made up of chitin is present in fungi.
- Cell wall is metabolically inactive but cell membrane is metabolically active.
- Cell wall protects the shape of the cell and maintains it while cell membrane protect the cytoplasm and osmotic balance in a cell.