cellpermeability

Cell permeability refers to the ability of a substance to pass through the cell membrane. The cell membrane is a selectively permeable barrier, meaning it allows some substances to pass through while restricting others. This selectivity is crucial for maintaining the cell's internal environment and carrying out its functions.

Permeability can be influenced by several factors, including the size, charge, and lipid solubility of the substance. Small, uncharged molecules like oxygen and carbon dioxide can often diffuse freely across the membrane. Larger molecules and charged ions typically require assistance from transport proteins embedded within the membrane. These proteins act as channels or carriers, facilitating the movement of specific substances.

The degree of permeability is not static; it can be regulated by the cell in response to various signals. For example, certain hormones can trigger changes in membrane permeability to ions like calcium, which plays a vital role in cell signaling and muscle contraction. Understanding cell permeability is fundamental to many areas of biology and medicine, including drug delivery, nutrient uptake, and the study of cellular processes.