Chapter 7.3 End of Chapter Assessment

16. A substance that moves by passive transport tends to move

C. Away from the area where it is more concentrated.

15. The movement of water molecules across a selectively permeable membrane is known as

D. Osmosis.

18. What is the relationship between diffusion and osmosis? By definition, what's the only substance that undergoes osmosis?

Diffusion and osmosis both regard the dispersion of particles. By definition, water is the only substance that undergoes osmosis.

17. Describe the process of diffusion, including a detailed explanation of equilibrium.

Diffusion is the intermingling of substances by the natural movement of their particles. Equilibrium is the state in which a process and its reverse are occurring at equal rates so that no overall change is taking place.

22. You are given food coloring and three beakers. The first beaker contains water at room temperature, the second beaker contains ice water, and the third beaker contains hot water. Design an experiment to determine the effects of temperature on the rate of diffusion. Be sure to state your hypothesis.

Drop an equal amount of food coloring into each beaker. My hypothesis for this experiment is that the hot water would diffuse the food coloring faster, due to the increased amount of molecular collisions (compared to the control group, the room temp. Water).

20. The beaker in the diagram below has a selectively permeable membrane separating two solutions. Assume that both water and salt can pass freely through the membrane. When equilibrium is reached, will the fluid levels be the same as they are now? Explain.

The diffusing salt particles and water molecules will eventually reach equilibrium without a change in the fluid on either side.

21. What would happen to a sample of your red blood cells if they were placed in a hypotonic solution?

The water would rush into the cell and the cell will explode.

19. What is the difference between passive transport and active transport?

Active transport is the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy; whereas, passive transport is a movement of biochemicals and other atomic or molecular substances across cell membranes. Unlike active transport, it does not require an input of chemical energy, being driven by the growth of entropy of the system.