TRANSPORT ACROSS MEMBRANES
SPRING 1999
INTRODUCTION TO SCIENCE
At the end of this section you need to be able to address the following:
  1. Explain the processes of diffusion, facilitated diffusion, active transport, exocytosis, and endocytosis.   How does these processes differ and how are they similar?
  2. What characteristics of the structure of cellular membranes allow regulation of what enters and leaves living cells?
  3. What factors influence the rate of diffusion across a cell membrane?  the rate of active transport?
  4. Where does the ATP that is used in active transport come from?
  5. To what, specifically, does osmosis refer?
  6. Plant and animal cells both change when placed in a hypertonic or hypotonic solution, but the changes are somewhat different.  What happens to animal

    7. cells when placed in a hypertonic solution?  a hypotonic solution?  How do these changes differ from those of a plant cell?
  7. To keep vegetables crisp, would you soak them in tap water or salt water?  Why?
  8. If you wanted your vegetable sticks to become crisp quickly, would you cut them into small or large pieces?  Why?
  9. Why is a control group important when conducting a scientific experiment?  What is the consequence(s) if a control group is missing?
  10. What is the importance of sample size when conducting a scientific experiment?  What is the consequence(s) is the sample size is small?

    11.