FOCUS ON: Osmosis [Plants]

Part 1 - Keywords:

1. Osmosis

2. Diffusion

3. Partially Permeable Membrane

4. Solution

5. Net Movement

6. Solute

7. Cell Membrane

8. Dilute Solution

9. Concentrated Solution

10. Turgid

11. Flaccid

12. Plasmolysis

13. Cell Wall

14. Aquatic

Part 2 - Key Facts:

Osmosis is the process of water molecules diffusing from a region of higher concentration to a region of lower concentration through a partially permeable membrane.

• A dilute solution has a high concentration of water molecules, while a concentrated solution has a low concentration.

• Osmosis specifically involves the movement of water molecules. When water concentration is equal on both sides of the membrane, there is no net movement.

• In living cells, which contain dilute solutions of ions, sugars, and amino acids, osmosis occurs through the partially permeable cell membrane.

Osmosis in Plant Cells:

• Isolated Plant Cells: In a dilute solution or water, plant cells take in water, becoming turgid due to the pressure exerted against the cell wall.

• Root Hair Cells: These cells absorb water by osmosis when the soil is wet or moist.

• Leaf Cells: In non-rainy or low-humidity conditions, leaf cells tend to lose water. The cellulose cell wall supports the cell, preventing bursting when gaining water by osmosis.

Plant Cell Responses to Different Solutions:

• Pure Water: Cells become turgid, supporting non-woody plant stems.

• Concentrated Solution: Cells lose water, becoming flaccid and plasmolysed.

• Highly-Concentrated Solution: Cells undergo full plasmolysis, losing more water.

• Environmental Conditions: Plants in dry soil or drought conditions may lose water by osmosis. Aquatic plants exposed to seawater or evaporation in rock pools may also experience water loss.

Part 3 - Quick Quiz:

1. What is osmosis?

2. a) Movement of solutes

   b) Movement of water molecules

   c) Movement of gases

   Answer: b) Movement of water molecules

3. What happens to plant cells in a dilute solution?

   a) They become turgid

   b) They become flaccid

   c) They undergo plasmolysis

   Answer: a) They become turgid

4. How does the cellulose cell wall support plant cells during osmosis?

   a) By preventing osmosis

   b) By being impermeable

   c) By preventing bursting

   Answer: c) By preventing bursting

Part 4 - Going Further:

Question: Explain the impact of osmosis on plant cells in different solutions. How does the cellulose cell wall contribute to the stability of plant cells during osmosis?

Answer: Osmosis in plant cells varies based on the concentration of the external solution. In dilute solutions, cells become turgid, supporting non-woody stems. In concentrated solutions, cells lose water, becoming flaccid and plasmolysed. The cellulose cell wall is crucial, preventing bursting during water gain and providing structural support.

Part 5 - Revision Tips: Focus on understanding the responses of plant cells to different solute concentrations and environmental conditions. Practice different scenarios to reinforce your knowledge.

Part 6 - More Help: WANT 25% Off GCSE Science And Math Tuition OR Past Paper Revision Resources? Click this link - piacademy.co.uk and use this COUPON CODE - GCSE25.

Stay tuned for the next issue, where we'll explore more captivating topics in GCSE Science.