How do osmosis and diffusion differ in terms of the movement of molecules?

• A. Osmosis and diffusion both involve the movement of solute molecules across a semipermeable membrane.
• B. Osmosis and diffusion both involve the movement of water molecules across a semipermeable membrane.
• C. Osmosis involves the movement of water molecules across a semipermeable membrane, while diffusion involves the movement of solute molecules.
• D. Osmosis involves the movement of solute molecules across a semipermeable membrane, while diffusion involves the movement of water molecules.

Answer: (C)

Verified step by step guidance

1. Understand the definitions: Osmosis is the movement of water molecules across a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration. Diffusion is the movement of solute molecules from an area of higher concentration to an area of lower concentration, not necessarily across a membrane.
2. Identify the key difference: Osmosis specifically involves water molecules, whereas diffusion involves solute molecules.
3. Consider the role of the semipermeable membrane: In osmosis, the semipermeable membrane allows only water molecules to pass through, not solute molecules. In diffusion, if a membrane is involved, it must be permeable to the solute molecules.
4. Analyze the direction of movement: In osmosis, water moves to balance solute concentrations on either side of the membrane. In diffusion, solute molecules move to achieve equilibrium in concentration throughout the available space.
5. Apply these concepts to the given options: The correct statement is that osmosis involves the movement of water molecules across a semipermeable membrane, while diffusion involves the movement of solute molecules.