Final answer:
The concept of semi-permeability is related to the structure of the plasma membrane by determining what substances can enter and leave the cell. The plasma membrane is selectively permeable, allowing certain substances to pass through while preventing others.
Step-by-step explanation:
The concept of semi-permeability relates to the structure of the plasma membrane by determining what substances can enter and leave the cell. The plasma membrane is selectively permeable, meaning it allows certain substances to pass through while preventing others. This selectivity is due to the structure of the membrane, which consists of a phospholipid bilayer with embedded proteins and carbohydrates.
For example, small, nonpolar molecules like oxygen and carbon dioxide can easily diffuse through the lipid bilayer of the membrane, while large molecules like proteins and ions require specific transport proteins or channels to cross the membrane.
This semi-permeability of the plasma membrane is crucial for maintaining homeostasis within the cell and regulating the movement of substances in and out of the cell.