Hand-write your answers on separate paper. Number your answers correctly.

Terms to Know:(Define All)

Homeostasis Metabolism Reproduction Heredity Lipid Bilayer Phospholipid

Selectively permeable Permeable Transport Proteins Passive Transport Active Transport Diffusion

Osmosis Osmotic Pressure Hypertonic Hypotonic Isotonic Facilitated Diffusion

Contractile Vacuole Kidney Tugor Pressure Wilting Endocytosis Exocytosis

Objectives: (Discuss the following objectives using complete sentences.)
(**Lab objective-discussion not required.)

1. Describe the characteristics of life.
2. Discuss how the structure of the lipid bilayer is related to its permeability.
3. Discuss how the structure and function of transport proteins help control permeability.
4. Compare the two methods cells use to maintain homeostasis. (Active and Passive Transport)
5. Discuss why osmosis is the greatest threat to cells.
6. **Investigate diffusion through a semi-permeable membrane.
7. Investigate and discuss the effects of different aqueous environments on cells. (Hypertonic, Hypotonic, and Isotonic solutions)
8. Discuss various methods in which organisms (bacteria, plants, animals, and protists) deal with osmotic pressure.
9. Compare the processes of endocytosis and exocytosis.

Practice Problems: Steps: Obj. #7

1. Determine if the solution is hypertonic, hypotonic, or isotonic by comparing the % of dissolved substances outside the cell to inside the cell.
2. Find the % of water in and out of the cell. (100% total -% salt=%water)
3. Due to osmotic pressure and the presence of a selectively permeable membrane, water will always diffuse through the membrane of the cell faster than the dissolved substances.
4. Osmosis is an example of passive transport. Draw an arrow, showing water flowing from an area where there is a higher concentration of water molecules to where there is a lower concentration of water.
5. Describe the effects of osmotic pressure on these cells. (Will the cell shrink, burst, or experience no osmotic pressure)
   (Use drawings to help show your work)

   #	Type of Cell	Solution cell is placed in
   1.	20% salt cell	30% salt solution
   2.	15% salt cell	15% salt solution
   3.	30% salt cell	10% salt solution
   4.	50% salt cell	0% salt solution
   5.	5% salt cell	10% salt solution

   6. Which of the above cells would be affected the most by its environment?
   
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