Osmotic Pressure in Biology: Real-World Examples

📚 Quick Study Guide

• 💧 Osmotic pressure is the minimum pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane.
• 🌱 It's crucial for plant cell turgor and overall plant health.
• 🔴 In animal cells, osmotic pressure affects cell volume and function, especially in red blood cells.
• 🧪 Formula: $\Pi = iMRT$, where $\Pi$ is osmotic pressure, $i$ is the van't Hoff factor, $M$ is molarity, $R$ is the ideal gas constant, and $T$ is temperature in Kelvin.
• 🍎 Examples include: Water absorption by plant roots, preservation of food using salt or sugar (like in jams and pickles), and the swelling or shrinking of cells in different solutions.

🧪 Practice Quiz

1. Which of the following BEST describes osmotic pressure?
   1. The pressure exerted by a gas in a closed container.
   2. The pressure required to prevent water from flowing across a semipermeable membrane.
   3. The pressure exerted by a solid on a surface.
   4. The pressure required to boil a liquid.
2. What happens to a red blood cell when placed in a hypertonic solution?
   1. It swells and bursts.
   2. It shrinks.
   3. It remains the same size.
   4. It undergoes mitosis.
3. Which component is NOT part of the osmotic pressure formula $\Pi = iMRT$?
   1. van't Hoff factor ($i$)
   2. Molarity ($M$)
   3. Volume ($V$)
   4. Ideal gas constant ($R$)
4. Why do plants wilt when they don't receive enough water?
   1. Due to increased turgor pressure.
   2. Due to decreased osmotic pressure and loss of turgor.
   3. Due to increased solute concentration in the soil.
   4. Due to decreased cell size.
5. Which of the following is an example of osmotic pressure in food preservation?
   1. Freezing vegetables.
   2. Adding salt to cure meat.
   3. Boiling fruits for canning.
   4. Refrigerating milk.
6. What is the van't Hoff factor ($i$) for glucose?
   1. 0
   2. 1
   3. 2
   4. 3
7. In osmosis, water moves from a region of ________ concentration to a region of ________ concentration.
   1. high solute, low solute
   2. low solute, high solute
   3. equal solute, equal solute
   4. high pressure, low pressure