Study Notes
Osmosis is the movement of water molecules from an area of high concentration to an area of low concentration through a semipermeable membrane.
- Osmosis — movement of water molecules through a semipermeable membrane from high to low concentration Example: Water moving from inside a raw mango to a brine solution, causing the mango to shrivel.
- Hypertonic solution — solution with a higher concentration of solute than the cell Example: Cells lose water and shrink in a hypertonic solution.
- Hypotonic solution — solution with a lower concentration of solute than the cell Example: Cells gain water and swell in a hypotonic solution.
- Isotonic solution — solution with an equal concentration of solute as the cell Example: No net movement of water in or out of cells in an isotonic solution.
Exam Tips
Key Definitions to Remember
- Osmosis: Movement of water molecules through a semipermeable membrane from high to low concentration.
- Hypertonic solution: Solution with a higher concentration of solute than the cell.
- Hypotonic solution: Solution with a lower concentration of solute than the cell.
- Isotonic solution: Solution with an equal concentration of solute as the cell.
Common Confusions
- Confusing osmosis with diffusion, which involves any type of molecule, not just water.
- Misunderstanding that osmosis requires a semipermeable membrane.
Typical Exam Questions
- What happens to a cell in a hypertonic solution? The cell loses water and shrinks.
- What is the result of placing a cell in a hypotonic solution? The cell gains water and swells.
- Why does a cell remain unchanged in an isotonic solution? Because there is no net movement of water in or out of the cell.
What Examiners Usually Test
- Understanding of how water moves in different types of solutions.
- Ability to identify and explain the effects of hypertonic, hypotonic, and isotonic solutions on cells.