Final answer:
Simple diffusion is not the net diffusion of a solvent; rather, it is the movement of a substance from an area of higher concentration to one of lower concentration without energy input. This process applies to molecules like oxygen and carbon dioxide, while osmosis specifically describes the diffusion of solvent molecules, such as water.
Step-by-step explanation:
The statement that simple diffusion is the net diffusion of a solvent is false. Simple diffusion actually refers to the movement of a substance due to differences in concentration without the aid of other molecules, and not specifically a solvent. This process involves molecules moving from an area of higher concentration to one of lower concentration, down their concentration gradient, until an equilibrium is reached.
Examples of substances that can undergo simple diffusion across cellular membranes include small hydrophobic molecules like oxygen (O2) and carbon dioxide (CO2), which are essential for the process of respiration. During simple diffusion, these molecules move because of their random thermal motion, which leads to a net movement from higher to lower concentration areas. This process does not require energy and is driven by the natural kinetic energy of the molecules involved.
An important distinction is that the diffusion of water molecules across a membrane is referred to as osmosis, which is also a passive process but is specifically about the solvent molecules moving through a semipermeable membrane. Simple diffusion and osmosis are both critical for maintaining homeostasis within cells and the body.