The cell membrane is a critical component of prokaryotic and eukaryotic cells; thus, plant cells also comprise a cell membrane. Opposed to animal cells, the cell membrane is not the outermost layer in plants, instead, they have the cell wall on the outside. While the cell wall provides rigidity to the eukaryotic cells, i.e., plant cells, the cell membrane is also an inevitable component of the cell. Let’s tell you about the function of cell membranes in plant cells in detail.
What is a Cell Membrane in a Plant Cell?
The cell membrane is a semi-permeable membrane that surrounds cells. It is present between the cytoplasm and the cell wall in the plant cell. The cell membrane in a plant cell is also known as the plasma membrane. The semi-permeability of the membrane allows a few molecules to pass through it. While the composition of the cell membrane is similar in all organisms, it might play additional roles in some organisms.
Functions of Cell Membrane in Plant Cell
The cell membrane performs versatile functions in the plant cell. It acts as the gatekeeper and barrier controlling the substances moving in and out of the cell. It also protects the components of the cell. Let’s tell you about the functions of cell membranes in plant cells in detail.
As the outermost layer of the plant cell is the cell wall, the cell membrane does not primarily contribute to providing a shape to the cell. But it still helps in keeping the cell organelles enveloped properly. On the other hand, the cell wall in plants is responsible for providing rigidity.
A major function of the cell membrane in the plant cell is its role in transporting material across the cell. The semi-permeability allows the passage of some molecules while others cannot. The lipid bilayer provides easy passage for small hydrophobic molecules like carbon dioxide and oxygen. At the same time, it stops the diffusion of large molecules like amino acids and sugars and charged molecules, including ions.
Some molecules cannot pass through the cell membrane independently and rely on membrane proteins. Various types of plasma membrane proteins contribute to the movement of specific ions and molecules. The movement of nutrients against the concentration gradient by these proteins requires more energy.
Cell Growth Maintenance
The cell membrane facilitates the maintenance of the cell by creating a balance between endocytosis and exocytosis. It ensures the cell does not deplete the nutrients required for growth and biological processes. Thus, when the cell eliminates waste products, it also takes in the required molecules.
Besides performing transport, the proteins in the cell membrane also play a role in communication and signaling. They often act as receptors for various molecules and allow them to perform their functions adequately.
Protection from Environment
The ability of the cell membrane to allow only specific molecules to pass through enables it to protect the inner environment from the outside. It ensures that the outer environment does not impact the cellular processes occurring within the cell.
Structure of Cell Membrane
The cell membrane has a complex structure comprising a lipid bilayer with embedded proteins and lipid molecules. The cell membrane may contain cholesterol, phospholipids, and extrinsic and intrinsic proteins. The cholesterol and proteins perform unique functions, making them an integral part of the cell membrane. They may also have carbohydrates in the form of glycolipids attached to the cell membrane.
The Bottom Line
The cell membrane is a critical part of the cell membrane that provides a shape to the cell and protects it from the external environment. The primary function of the cell membrane in plant cells is to ensure transportation within and outside of the cell. Besides the transport of molecules due to semi-permeability, membrane proteins also contribute to the movement of molecules. The endocytic and exocytic activities of the cell membrane ensure the maintenance of the cell environment.
Do all plant cells have a cell membrane?
Yes, all plants have a cell membrane next to the cell wall. It is present between the cell wall and the cytoplasm and helps differentiate the internal environment from the external.
What is a plant membrane made of?
The plant cell membrane comprises multiple molecules, including lipids, proteins, and carbohydrates. All these molecules contribute to unique functions within the cell. Some are embedded within the membrane, while others can be seen on either side.
What is the membrane system in plants?
The cell membrane performs various functions in the plant cell besides transporting materials. The proteins in the cell membrane play a role in metabolic activities and communication across the cell.
Which membrane is present only in plants?
Only plants have a membrane called the Glyoxysome. Plants also have a cell wall that is absent in animal cells; however, fungi and prokaryotes contain a cell wall too.
Anna has completed her degree in Pharmacy from the University of Hawaii. She is serving as a research assistant in a pharmaceutical company. She had a great interest in writing blogs, traveling to different parts of the US, and trying delicious recipes in her spare time.