2B.4 Active transport

• give and example of co-transportation in the body, and explain the process.

  glucose into the ileum. • Na+ is actively transported out of epithelial cells into the blood via the Na/K pump causing a conc gradient (higher in ileum and lower in cells) • Na+ diffuses from ileum into the cells via the Na+/glucose co transporter, diffusing glucose with it. • this causes a glucose conc gradient (higher in cells than blood) allowing it to facilitatedly diffuse into the blood.
• what is co-transportation?

  when carrier proteins bind two molecules at the same time and diffuse them using the concentration gradient of one to move the other.
• give an example of active transport in humans.

  reabsorption of molecules and ions into the blood after filtration into the kidney tubules.
• give one example of active transport in plants.

  inorganic ions from soils to root hair cells.
• compare facilitated diffusion with active transport.

  Facilitated: • down a conc gradient.• carrier and channel proteins. • uses innate kinetic energy.• selective.active transport: • against a conc gradient.• carrier proteins only.• energy from ATP.• selective.
• how is ATP used in active transport?


  • ATP undergoes hydrolysis. • the P binds to the carrier protein causing it to change shape. • the molecule travels through the opened channel. • P is released and recombines with ADP, and the protein returns to its original shape.
• what are the two main differences between active transport and facilitated diffusion?

  • active transport goes against the concentration gradient. • active transport requires energy from ATP.
• how do carrier proteins work in active transport?

  • a molecule attaches to a carrier protein. • the protein changes shape. • the molecule is released on the other side.
• what is active transport?

  the net movement of particles against a concentration gradient through carrier proteins and co transporters using energy.