Simple and facilitated diffusion 1. Why is transport across the plasma membrane necessary for a cell? __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 2. Why can some substances cross the plasma membrane unassisted while others cannot? __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 3. In the spaces provided below, explain how each feature effects transport across the plasma membrane Molecule size __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ Presence of net charge (+ or -) __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ Solubility in lipids __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ Direction of concentration gradient __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 4. List what type of substance can easily cross the plasma membrane (polar or non-polar? Lipid soluble or water soluble? Large or small?) __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 5. List what substances cannot easily cross the plasma membrane (polar or non-polar? Lipid soluble or water soluble? Large or small?) __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 6. What is meant by the term “simple diffusion”? __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 7. What is meant by the term “facilitated diffusion”? __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 8. What structure within the plasma membrane is required for facilitated diffusion to occur? Name the who variations of this structure involved in facilitated diffusion. __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 9. What is the diffusion of water called? __________________________________________________________________________________ __________________________________________________________________________________ 10. What kind of substances can be transported using simple diffusion? __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 11. What kind of substances can be transported using facilitated diffusion? __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 12. Simple and facilitated diffusion are both categorised as what type of transport? __________________________________________________________________________________ __________________________________________________________________________________ 13. What direction do substances move in passive transport? (with or against the concentration gradient?) __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 14. Does passive transport require an input of energy? __________________________________________________________________________________ __________________________________________________________________________________ 15. In the image below, label where the higher and lower concentration is and draw an arrow showing the movement of substances in passive transport. 16. What factors can affect the rate of diffusion? __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________
