I. Define the following terms in complete sentences:


 

 


II. Suppose that you have an diffusion/osmosis apparatus similar to the one that you used in the exercise. In one side of the apparatus, there are a 100 mL of solution composed of distilled water and iodine. In the other side, there is a 10% starch solution. The liquid levels in both sides are initially the same. Answer the following questions in complete sentences.

a. What will happen to the level of the water and iodine solution (Side A)?

b.  Explain why this will occur.

c. What will happen to the color of the water and iodine solution? Why?





d. What will happen to the color of the starch solution? Why?



III. Often when a person is ill they must be given fluids intravenously (by injection directly into the blood vessel). Why must the person never be given pure water intravenously? Be sure to explain your answer in full, using the concepts of diffusion and osmosis that we have discussed.





1V.   Describe the process by which the red onion pictured in the diagram at the left can be made to appear like the diagram at the right using a substance you will identify, a piece of paper towel, and an eyedropper.   You are not allowed to raise the cover slip on the slide.



V.  What process is responsible for the changes observed above?




VI.   Describe a technique which could make this process go in reverse.

 





 

 

 

 

 

VII.  Based on the osmosis/diffusion lab we completed.

 

(a.) define diffusion


(b.) list the two substances that diffused through the membrane



(c.) Using at least two complete sentences, explain how it was

       proven that  these substances did diffuse through the membrane?



(d.) which substance did not diffuse through the membrane



(e.) How was this proven that this substance did not diffuse through

       the membrane?



(f.)  Using a complete sentence, state the major factor which appears

       to determine whether or not substances pass through

       our membranes

Choose the answer which best completes the following statements or answers the following questions.

1. The arrows in the diagram represent the direction of movement of a certain type of molecule through the cell membrane of two different cells. The dots represent the relative concentrations of this molecule. Which processes are illustrated in the diagram?

 

 

(1.) phagocytosis and diffusion (2.) active transport and diffusion   (3.) pinocytosis and osmosis
(4.) dehydration synthesis and circulation

 

 2. The process of osmosis would explain the net movement of water into a cell if the percentage of

 

(1.) water was 90% inside the cell and 95% outside the cell 
(2.) water was 95% inside the cell and 90% outside the cell

(3.) protein was 30% inside the cell and 35% outside the cell
(4.) water and protein was equal inside and outside the cell

View the Diffusion through a Membrane Lab Quiz Answers