Question

What is plasmalemma?

Answer 1

Hint Plasmalemma has the word plasma in it, hence it is related to something that contains plasma. Plasmalemma is a structure present in eukaryotic cells. It is related to the cell membrane that is present in animal cells.

Complete answer:
- Plasmalemma is a plasma or cell membrane that is mainly found in plants.
- It is a semipermeable membrane that encloses the cell’s cytoplasm and nucleoplasm and separates the cell from the extracellular fluid.
- It consists of a lipid bilayer that is embedded with proteins that carry out various functions apart from enzymatic activity, and cholesterols.
- The complexity of the membrane makes it semi permeable to organic molecules and ions.
- It serves as an attachment surface for the cell wall, the glycocalyx, and the cytoskeleton.

Additional Information: - The cell membrane consists of three classes of amphipathic lipids (lipids with both hydrophilic and lipophilic properties): phospholipids, glycolipids, and sterols.
- The proteins present on the plasma membrane include (but are not limited to) membrane proteins such as membrane transporters and peripheral proteins.
- Cholesterol is present between the two phospholipid layers and it helps in maintaining its fluidity at various temperatures.
- The cell membrane is involved in other functions such as cell adhesion, ion conductivity, and cell signaling.

Note: - Plasmalemma as a term is becoming obsolete and plasma membrane or cell membrane are being used as terms more commonly.
- Plant cells contain a cell wall that surrounds the cell membrane providing rigidity and support.
- While the cell membrane is formed of phospholipids in most prokaryotes and eukaryotes, the cell membrane in archaea are composed of ether lipids.