Biology Lecture: Passive and Active Transport

Introduction

• Teacher: Janet
• Chapter: Form Four Chapter Three
• Subtopics Discussed:
  • 3.2 Passive vs Active Transport
  • 3.3 Passive and Active Transport in Organisms

Passive Transport

• Analogies:
  • Compared to a person riding a bicycle downhill (no energy required).
• Characteristics:
  • Movement of substances from high concentration to low concentration.
  • Does not require energy.
• Types of Passive Transport:
  • Simple Diffusion: Movement through phospholipid bilayer (e.g., oxygen, carbon dioxide).
  • Osmosis: Diffusion of water through phospholipid bilayer.
  • Facilitated Diffusion: Requires carrier or channel proteins to transport substances.

Active Transport

• Analogies:
  • Compared to a person cycling uphill (energy required).
• Characteristics:
  • Movement of substances from low concentration to high concentration.
  • Requires energy (ATP).
  • Utilizes carrier proteins.

Learning Standards

1. Compare and contrast passive and active transport.
2. Explain passive transport in organisms with examples.
3. Explain active transport in organisms with examples.

Concept Map

• Movement Across Plasma Membrane:
  • Divided into: Passive Transport and Active Transport.
  • Passive Transport: Simple Diffusion, Osmosis, Facilitated Diffusion.
  • Active Transport: Requires carrier proteins and energy.

Types of Transport

Simple Diffusion

• Process: Movement from high to low concentration.
• Examples: Lipid-soluble molecules, oxygen, carbon dioxide.

Osmosis

• Process: Movement of water from high to low concentration.

Facilitated Diffusion

• Process: Requires proteins (channel or carrier) for transport.
• Examples: Ions (Ca, Cl) through channel proteins, large molecules (amino acids, glucose) through carrier proteins.

Active Transport

• Process: Movement from low to high concentration against gradient.
• Examples: Sodium-potassium pump, transport of potassium ions.

Passive vs Active Transport

• Passive Transport:
  • Moves substances down concentration gradient.
  • No energy required.
• Active Transport:
  • Moves substances against concentration gradient.
  • Energy required.
• Similarities: Both occur in living organisms through semi-permeable membranes.

Examples in Organisms

Passive Transport

• Gaseous Exchange: Oxygen and carbon dioxide exchange in lungs.
• Absorption of Water: Osmosis in plant root hairs.

Active Transport

• Mineral Ion Absorption: In plant root hairs, requires energy.
• Absorption of Glucose and Amino Acids: In the villi via active transport.

Formative Practice

Question 1: Spraying Water on Produce

• Purpose: Prevent wilting.
• Process: Water diffuses into cells via osmosis, maintaining turgidity.

Question 2: Sprinkling Sugar on Strawberries

• Process: Sugar solution becomes hypertonic, causing plasmolysis as water leaves cells.

Conclusion

• Key takeaways include differences between passive and active transport, and specific examples in organisms.
• Focus on understanding concepts and processes through analogies and applications in real-life organisms.