2.1 Types of Movement of Substances
- Diffusion: Movement of particles from high to low concentration.
- Osmosis: Movement of water from high water potential to low water potential through a semi-permeable membrane.
- Active Transport: Movement of particles against a concentration gradient using energy (ATP).
2.2 Diffusion
- Factors Affecting Diffusion:
- Concentration Gradient: Faster diffusion with a steeper gradient.
- Temperature: Faster diffusion at higher temperatures.
- Surface Area: Larger surface area = faster diffusion.
- Distance: Shorter distance = faster diffusion.
2.3 Osmosis
- Example: Root hair cells absorbing water from soil.
- Effects on Cells:
- Animal Cells: In pure water, they may burst (lysis). In concentrated solutions, they shrink (crenation).
- Plant Cells: Become turgid (firm) in pure water, plasmolyze (shrink) in concentrated solutions.
2.4 Active Transport
- Example: Absorption of minerals by root cells.
- Requires energy: From respiration.
2.5 Importance of Movement of Substances
- Diffusion: Gas exchange (O2, CO2) in lungs.
- Osmosis: Maintains water balance in cells.
- Active Transport: Uptake of minerals against concentration gradients.