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University of North CarolinaBIOL 101 Membrane Structure and Function 1)The chapter opener discusses aquaporins

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1. 2. What kinds of molecules use facilitated diffusion (a kind of passive transport that requires transporter proteins)?

 

 

 

6. If I give you a 5% sucrose solution and a 10% sucrose solution, in which is the water less concentrated?

 

 

7. When water moves through a selectively permeable membrane down its concentration gradient this is termed
8. Is seawater hypertonic, isotonic, or hypotonic to drinking water?

 

 

9. If a hypotonic solution is put in a selectively permeable membrane and put into a hypertonic solution, what will happen to the bag over time? (shrink or swell?) Why? Where is the water more concentrated?

 

10. Water is a polar molecule and thus diffuses slowly into cells. What type of membrane protein would you expect to find many of in a cell that must be highly permeable to water?

 

 

11. Scientific Thinking in Module 5.7: Sometimes discovery is accidental. What type of cell did Dr. Agre’s team accidentally discover aquaporins in?

 

In their work, shown in Figure 5.7 control frog eggs were compared to frog eggs that carried genetic information to make many aquaporins. What result did they get when they put these two groups of eggs in a hypotonic situation (describe Figure 5.7).

What did it tell them about the function of aquaporins?

 

 

12. In our discussion of how cells use glucose as an energy resource, we will see that cells are continually bringing glucose in from the blood where the concentration is higher. What kind of transport does glucose use?

 

 

10. How do calcium ions move against their concentration gradient?

 

 

11. Compare and contrast exocytosis and endocytosis.

What are the distinctions between phagocytosis and receptor-mediated endocytosis?