Which of the following best describes the main difference between osmosis and diffusion in cells?

• A. Osmosis is the movement of solutes, while diffusion is the movement of water.
• B. Osmosis involves the movement of water across a selectively permeable membrane, while diffusion involves the movement of any type of molecule from an area of high concentration to low concentration.
• C. Osmosis and diffusion both require energy input from the cell to occur.
• D. Diffusion only occurs in plant cells, while osmosis only occurs in animal cells.

Answer: (B)

Verified step by step guidance

1. Step 1: Begin by understanding the definitions of osmosis and diffusion. Osmosis is the movement of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. Diffusion, on the other hand, is the movement of molecules (not limited to water) from an area of high concentration to an area of low concentration, driven by the concentration gradient.
2. Step 2: Analyze the first option: 'Osmosis is the movement of solutes, while diffusion is the movement of water.' This is incorrect because osmosis specifically refers to the movement of water, not solutes.
3. Step 3: Evaluate the second option: 'Osmosis involves the movement of water across a selectively permeable membrane, while diffusion involves the movement of any type of molecule from an area of high concentration to low concentration.' This aligns with the definitions of osmosis and diffusion and is likely the correct answer.
4. Step 4: Examine the third option: 'Osmosis and diffusion both require energy input from the cell to occur.' This is incorrect because both osmosis and diffusion are passive processes that do not require energy input from the cell.
5. Step 5: Review the fourth option: 'Diffusion only occurs in plant cells, while osmosis only occurs in animal cells.' This is incorrect because both osmosis and diffusion occur in all types of cells, including plant and animal cells. Based on this analysis, the second option is the best description of the main difference between osmosis and diffusion.