Transport

Introduction

Cells must transport water and other essential molecules into and out of itself across the plasma (cell) membrane.  Understanding the vehicles of molecular transportation is necesarry for realizing how organelles must function together to maintain a homeostatic environment.  The external environment will have an impact on the type and amount of molecular trasnport taking place at the cellular level.  Understanding the environmental impact on molecular transport will enable one to predict how and why cells will act/react in certain environments.

Task

Molecular transport occurs in two ways. Passive transport is the movement of molecules without the use of energy.  Active trasnport is the movement of molecules with the use of energy.  One must be able to identify the type of transport the advantages/disadvantages of each.  

Process

I. Understand the relation of molecules and membranes. Use the link to answer the questions.

http://www.wiley.com/college/pratt/0471393878/student/animations/membra…

1. What compounds are commonly exchanged across membranes?

2. What is the lipid bilayer fairly permeable to? Impermeable to?

3. What does hydrophobic mean?

4. Why is the cell membrane hydrophobic? Illustrate.

5. What part of the cell membrane links the interior of the cell with the extracellular fluid?

6. What is passive transport?

7. What is equillibrium?

8. What is active transport?

Evaluation
Conclusion

The process of homeostasis in vital for the survival of living organisms.  In order for cells to maintain a stable internal environment, cells must intake the proper nutrients and remove the unwanted waste products.  The intake and removal of these materials must be accomplished efficiently, yet remain effective as well.  The unique combination of passive and active transport are the two mechasims cells utilize to accomplish a homeostatic state.