Question

Which one of the following is an example of osmosis?

1) Diffusion of water across a semipermeable membrane
2) Movement of molecules from an area of high concentration to an area of low concentration
3) Transport of ions across a cell membrane
4) Exchange of gases in the lungs

Answer 1

Osmosis is the movement of water through a semipermeable membrane from an area of high water concentration to an area of low concentration, facilitated by aquaporins.

Step-by-step explanation:

Osmosis Explained

Osmosis is a type of diffusion specifically involving the movement of water across a semipermeable membrane. It occurs when water moves from a region of high water concentration to a region with lower water concentration, which is inversely proportional to the concentration of solutes. This movement is due to the presence of a concentration gradient, and the process continues until the concentrations are equal on both sides of the membrane.

Osmosis is facilitated by proteins called aquaporins, which are integral in the rapid transport of water across cell membranes. Unlike simple diffusion which can pertain to various types of molecules, osmosis refers specifically to the transport of water. Therefore, when given options on which process is an example of osmosis, the correct answer is the diffusion of water across a semipermeable membrane.