Active Transport

• What is active transport?

  Movement of molecules against a concentration gradient
• How does solute concentration affect water potential?

  Increasing solute concentration decreases water potential
• What happens to an animal cell in a hypertonic solution?

  The cell shrinks and becomes crenated
• What is the outcome for a plant cell in a hypotonic solution?

  The cell becomes turgid but does not burst
• How is osmosis different from diffusion?

  Osmosis involves water and requires a membrane
• What is plasmolysis in plant cells?

  Loss of water causing the membrane to pull away
• What are the conditions required for active transport?

  • Requires ATP
  • Moves substances against a concentration gradient
  • Involves carrier proteins
• What type of energy is required for active transport?

  ATP
• In which direction do substances move during active transport?

  Against the concentration gradient
• What role do carrier proteins play in active transport?

  They act as "pumps" to move substances
• Why is active transport considered a selective process?

  It only transports specific substances
• How does active transport differ from passive transport in terms of energy usage?

  Active transport uses ATP; passive does not
• Why are carrier proteins often referred to as "pumps" in active transport?

  They actively move substances using ATP
• Describe the process of direct active transport of a single molecule or ion.

  1. Carrier proteins bind to the molecule or ion.
  2. Molecule attaches to receptor sites on the protein.
  3. ATP binds, splitting into ADP and phosphate.
  4. Shape change transports the molecule across the membrane.
  5. Molecule is released on the other side.
  6. Phosphate is released, protein reverts to original shape.
• Compare active transport and facilitated diffusion.

  • Both use carrier proteins
  • Facilitated diffusion occurs down a gradient
  • Active transport occurs against a gradient
  • Facilitated diffusion does not require energy
  • Active transport requires ATP
• What is the sodium-potassium pump's function?

  Moves sodium out and potassium into the cell
• What provides energy for active transport?

  ATP
• What happens when ATP binds to a carrier protein during active transport?

  The carrier protein changes shape to transport the molecule
• Which process is used by the sodium-potassium pump?

  Active transport of sodium out and potassium in
• How does facilitated diffusion differ from active transport?

  Facilitated diffusion does not require ATP
• What are the key differences between active transport and passive transport?

  • Active transport requires ATP
  • Active transport moves against a concentration gradient
  • Passive transport occurs down a concentration gradient
  • Active transport is selective for specific substances