Functional characteristics of cell membrane_Functional characteristics of cell membrane

There are countless cells in our body. Only with these cells can we function normally. Moreover, our cells have certain metabolic functions. They can distinguish many daughter cells. After the daughter cells are divided, the mother cells will automatically disappear. This metabolic function can improve our body's resistance. Cells also have a layer of cell membrane, so what are the functional characteristics of the cell membrane?

The "structural characteristics" of the cell membrane refer to the fluidity of the cell membrane (including the fluidity of membrane lipids and the mobility of membrane proteins); while the "functional characteristics" of the cell membrane refer to the selective permeability of the cell membrane.

2. Structural Basis The phospholipid bilayer constitutes the basic support of the cell membrane, and protein molecules are embedded, penetrated, and covered in between. The fluidity of phospholipid molecules and the mobility of protein molecules lead to a certain fluidity of the structure of the cell membrane. The cell membrane has the function of controlling the entry and exit of substances into and out of the cell. Substances enter and exit the cell in the form of free diffusion, assisted diffusion, active transport, endocytosis, and exocytosis. The types and quantities of carrier proteins on the cell membrane are different, which determines the types and quantities of substances entering and exiting the cell. Therefore, the cell membrane allows water molecules to pass freely, and some ions and small molecules can also pass through, while other ions, small molecules, and macromolecules cannot pass through. Therefore, the functional characteristic of the cell membrane is selective permeability.

3. The relationship between the two Fluidity is the basis of selective permeability. It is precisely because of the fluidity of membrane lipids and the mobility of membrane proteins that the function of the cell membrane to control the entry and exit of substances is determined, thus reflecting selective permeability.

IV. Influencing factors

1. Temperature. Temperature affects molecular movement and thus membrane fluidity. Within a certain range, as temperature rises, membrane fluidity increases, which is beneficial to the physiological function; but if the temperature is too high, the membrane fluidity is too large, which will damage the membrane structure, be detrimental to the life activities, and even cause cell death; if the temperature is too low, the membrane fluidity decreases, the viscosity increases, the transport function decreases, and the membrane structure is seriously damaged, the permeability increases, and the contents are discharged in large quantities, causing cell death. Temperature affects the activity and motility of membrane proteins, thus affecting the selective permeability of cell membranes.

2. PH. Excessive acidity or alkalinity will denature and inactivate the proteins in the cell membrane, thus causing the cell membrane to lose its physiological functions.

3. Proteases, lipid solvents, etc. Proteases can hydrolyze membrane proteins, and lipid solvents can dissolve membrane lipids, thereby destroying the membrane structure and causing the cell membrane to lose its physiological function.