NAME:_______________________________ PERIOD:_______________

 

DATE:_______________________  DATE DUE:_____________________

 

TONICITY

 

Color and label figure 3.3:                           Label only:

1. solute-red                                                   3. Cell membrane

2. solvent (water)-blue

 

 

QUESTIONS:

1. According to figure 3.3, does the solute cross the cell membrane?_________________

 

2. Does the water cross the cell membrane?_____________________________________

 

3. This movement of water across the cell membrane is called _____________________.

 

4. The percentages shown represent the concentration of ______________(solute, water).

 

5. The cell in figure 3.3a has __________(high, low, the same) concentration of solute when compared with the surrounding hypotonic solution.

 

6. Therefore, the cellís water concentration is ________ (high, low, the same) when compared with the surrounding hypotonic solution.

 

7. When placed in a hypotonic solution, water _______________( enters, leaves) the cell.

 

8. What happens to the cell size in a hypotonic solution? __________________________

 

9. This process is called ____________________________________________________

 

10. The cell in figure 3.3b has __________(high, low, the same) concentration of solute when compared with the surrounding isotonic solution.

 

11. Therefore, the cellís water concentration is ________ (high, low, the same) when compared with the surrounding isotonic solution.

 

12. What happens to the cell size in a isotonic solution? _________________________

 

13. The cell in figure 3.3c has __________(high, low, the same) concentration of solute when compared with the surrounding hypertonic solution.

 

14. Therefore, the cellís water concentration is ________ (high, low, the same) when compared with the surrounding hypertonic solution.

 

15. When placed in a hypertonic solution, water _____________( enters, leaves) the cell.

 

16. What happens to the cell size in a hypertonic solution? ________________________

 

17. This process is called ___________________________________________________

 

18. Is the concentration gradient for the solute in the same or the opposite direction as the concentration gradient for the water? _______________________________________

 

19. Does a solute or water concentration gradient exist for cells in an isotonic solution?

 

20. For cells in an isotonic solution, does the movement of water across the membrane stop?  Explain your answer. _________________________________________________

 

CELLULAR TRANSPORT

 

The diagrams below represent the three types of solutions: isotonic, hypotonic and hypertonic.  Draw arrows in indicate the net flow of water into or out of the cell for each of the diagrams.

 

 

 

 

1. Indicate which type of solutions are shown in each of the three diagrams:

 

A. _________________________________

 

B. _________________________________

 

C. _________________________________

 

2. Which diagram show no concentration gradient? ________________

 

3. Which diagram represents a situation in which the cell will shrivel up and lose its shape? _____________________________________________________________

 

4. What is this situation is question 3 called? ________________________________

 

Study the diagram below then answer the following questions:

 

1. Molecules of substance A are shown be triangles.  This substance is in greater concentration ________________________________ (inside, outside) the cell.

 

2. The notches in the plasma membrane represent _______________________________ (phospholipids, proteins or cholesterol).

 

3. Molecules of substance A are moving _______________________ (with, against) the concentration gradient.

 

4. This movement requires the cell to _________________________________________.

 

5. When such movements occur across the cell membrane, are they considered to be passive or active transport? _________________________________________________

 

Study the diagram of the beakers below, noting the concentrations of various substances in the beakers and in the cellulose bags.  Water molecules can pass through the cellulose, but starch cannot.   Draw arrows in the diagrams to show the direction in which water will move then answer the following questions:

 

 

1.      Which of the two beakers contains a solution that is hypertonic relative to the bagís contents. ______________________________________________________________

 

2.      What will eventually happen to the concentrations of the solutions inside and

outside the bag in beaker 2? _______________________________________________

 

3.      Will the same thing happen in beaker 1? ________ Why or why not? ______________

 

4.      The bag in which beaker will experience a rise in osmotic pressure? _______________

 

5.      What will eventually happen as the pressure rises? _____________________________

 

6.      Cells behave much like the cellulose bag.  When such movements occur across the cell membrane, are they considered to be passive or active transport? ___________________