Homeostasis Worksheet Ch5 BI


Homeostasis & Transport


Section 5-1 Passive Transport

1. What is the purpose of the cell membrane?

2. Explain passive transport.

3. What is the simplest type of passive transport?

4. In which direction does diffusion occur?

5. What is a concentration gradient?

6. Sugar dissolving in water is an example of _______________________.

7. What supplies the energy for diffusion?

8. Molecules are constantly _____________________.

9. What is meant by equilibrium?

10. Do molecules stop moving when equilibrium is reached? Explain.

11. List three things that determine if a molecule will be able to diffuse across a membrane.

12. Name the 2 parts of a solution.

13. Define osmosis. Is it passive or active transport?

14. The direction water moves across a cell membrane depends on the concentration of what on either side of the cell membrane?

15. Explain what is true about solutes if the outside of the cell is hypotonic to the cytosol? Which way does water move?

16. Explain the solute conditions if the outside is hypertonic to the cytosol. Which way does water move?

17. What occurs if the solute concentration on each side of the cell membrane is isotonic?

18. If the inside & outside of a cell are both isotonic, does water still move across the cell membrane? Explain.

19. If the inside of the cell is hypotonic, the outside will be _________________________.

20. Water tends to diffuse from ____________________ to ___________________ solutions.

21. How does a unicellular paramecium get rid of its excess water? Is energy used?

22. Many cells in multicellular organisms have _________________ pumps to prevent them from taking in too much water in hypotonic solutions.

23. What structure around the outside of plant cells keeps hem from rupturing from too much water?

24. What is turgor pressure & how does it help plant cells?

25. What happens to plant cells placed in a hypertonic solution? Name this process.

26. What is cytolysis & what causes it?

27. Another type of passive transport is __________________________ diffusion.

28. Explain how carrier proteins help in facilitated.

29. Sketch the changes that take place in a carrier protein as it helps molecules move across the cell membrane.

30. What sugar moves across the cell membrane by facilitated diffusion?

31. What are ion channels & are they used in passive or active transport?

32. Name 4 ions that cross the cell membrane through ion channels.

33. Why can’t these ions diffuse across the lipid bilayer of the cell membrane?

34. Ion channels may be always ________________ or have ___________________.

35. Name 3 stimuli that open & close gated channels.

Section 5-2 Active Transport

36. Define active transport.

37. Why are carrier proteins in the cell membrane that are used for active transport called “pumps”?

38. What is the best-known carrier protein pump in animal cells?

39. What 2 ions move up their concentration gradient in this pump?

40. ___________________ ions are pumped out, while ______________ ions are pumped into the cell.

41. Is energy required for active transport? Explain.

42. Sodium ions are exchanged for potassium ions at a ____________ to ____________ ratio.

43. Name 2 processes used to move macromolecules & food particles across the cell membrane. Is energy required?

44. Explain how cells move large particles into the cell by endocytosis.

45. Name & describe the 2 types of endocytosis.

46. How do phagocytes protect cells?

47. What process moves large materials such as wastes & proteins out of the cell?