___

1. 1. The plasma membrane is composed primarily of _____. A. phospholipids B. carbohydrates C. waxes D. nucleic acids ___

2. 2. The tails of the phospholipids are _____. A. nonpolar B. hydrophobic C. directed inwards in the bilayer D. all of the above ___

3. 3. The amount of phospholipid extracted from red blood cells led researchers to propose that ____. A. the phospholipids form a single layer around the cell B. the phospholipids form a bilayer around the cell C. there are not enough phospholipids to create a membrane around the cell ___

4. 4. Electron micrographs support the _____ model of the plasma membrane. A. sandwich B. unit membrane C. fluid-mosaic ___

5. 5. According to the fluid-mosaic model, _____ are partially or wholly embedded in a fluid phospholipid bilayer. A. nucleic acids B. monosaccharides C. proteins D. triglycerides ___

6. 6. All membranes appear the same in electron micrographs. True False ___

7. 7. The plasma membrane is permeable to some nonlipid substances. True False ___

8. 8. According to the fluid-mosaic model the hydrophilic heads of the phospholipids face the intra and extracellular fluids. True False ___

9. 9. Phospholipids are the only type of lipid in the plasma membrane. True False ___

10. 10. The permeability of most membranes is reduced by the presence of _____ in the membrane. A. nucleotides B. proteins C. cholesterol D. glycolipids ___

11. 11. A sugar attached to a lipid is called a _____. A. glycoplipid B. disaccharide C. monomer D. glycoprotein ___

12. 12. The plasma membrane is "sugar-coated" by _____. A. glycolipids B. gylcoproteins C. both A and B ___

13. 13. The proper functioning of some of the membrane proteins depends on the fluidity of the membrane. True False ___

14. 14. Which of the following lipids may be found in the plasma membrane? A. phospholipids. B. cholesterol. C. glycolipids. D. all of the above. ___

15. 15. The two halves of the plasma membrane are identical. True False ___

16. 16. The plasma membrane is a stiff and rigid structure. True False ___

17. 17. Glycolipids and glycoproteins vary from __________. A. species to species B. individual to individual C. cell to cell D. all of the above ___

18. 18. Particular molecules or ions freely cross the plasma membrane with assistance from _____. A. receptor proteins B. cell recognition proteins C. channel proteins D. enzymatic proteins ___

19. 19. Transplant rejections are the result of the immune system's response to foreign glycoproteins and glycolipids. True False ___

20. 20. A person's blood type is determined by the presence of particular _____ in the red blood cells' membranes. A. phospholipids B. glycoproteins C. steroids D. nucleic acids ___

21. 21. Receptor proteins in the plasma membrane bind to any kind of molecule. True False ___

22. 22. The "fingerprints" of the cell are _____. A. the carbohydrate chains of glycolipids and glycoproteins B. the sequence of amino acids in the channel proteins C. the types of fatty acids in the phospholipids D. the phosphate groups of the phospholipids ___

23. 23. Peripheral proteins are found within the plasma membrane. True False ___

24. 24. Lipid-soluble molecules move freely across the plasma membrane. True False ___

25. 25. Which of the following does NOT move freely (without energy or a carrier protein) across the plasma membrane? A. H2O B. steroids C. Na+ D. O2 ___

26. 26. Which of the following requires energy? A. diffusion B. active transport C. osmosis D. facilitated transport ___

27. 27. During diffusion molecules move from areas of low concentration to areas of high concentration. True False ___

28. 28. The hydrophobic tails of the phospholipids in the plasma membrane are what prevent ions and charged molecules fromfreely crossing the membrane. True False ___

29. 29. The sugar you stir into your coffee is an example of a _____. A. solvent B. solute ___

30. 30. Osmosis is specifically about the movement of _____ in and out of cells. A. sugars B. proteins C. water D. oxygen ___

31. 31. If the inside of a cell is 1% NaCl, which solution is isotonic to the cell? A. 0.01% NaCl B. 0.1% NaCl C. 1% NaCl D. 10% NaCl ___

32. 32. If the inside of a cell is 1% NaCl, which solution is hypertonic to the cell? A. 0.01% NaCl B. 0.1 % NaCl C. 1% NaCl D. 10% NaCl ___

33. 33. Plants wilt when you don't water them due to decreased turgor pressure . True False ___

34. 34. A hypotonic solution has fewer solutes than the cell. True False ___

35. 35. Macromolecules are transported into the cell by __________. A. exocytosis B. osmosis C. diffusion D. pinocytosis ___

36. 36. Solutions that cause cells to neither gain nor lose water are known as ______ solutions. A. isotonic B. hypertonic C. hypotonic ___

37. 37. When a plant cell is placed in a hypotonic solution which of the following will occur? A. The cell will swell and burst. B. nothing C. The central vacuole gains water. D. The cell will shrink or shrivel up. ___

38. 38. The term hemolysis refers to ______. A. normal red blood cells B. red blood cells that burst after being placed in a hypotonic solution C. shrinking of the cytoplasm after a cell is placed in a hypertonic solution D. the loss of turgor pressure in a plant cell ___

39. 39. Carrier proteins are required for _____. A. osmosis B. facilitated transport C. active transport D. both B and C ___

40. 40. Osmotic pressure affects _____. A. water retention by the kidneys B. water uptake from tissue fluids by the capillaries C. water absorption from the large intestine D. all of the above ___

41. 41. The chloride ion channels malfunction in persons with __________, leading to the symptoms of this inheriteddisease/disorder. A. diabetes B. Down syndrome C. cystic fibrosis D. AIDS ___

42. 42. Which of the following correctly describes facilitated transport? A. It requires the expenditure of energy. B. Molecules move from high concentration to low concentration. C. Vacuoles form to move materials. D. all of the above ___

43. 43. Which of the following correctly describes active transport? A. carrier proteins are needed. B. it requires the expenditure of energy. C. molecules move from areas of low concentration to areas of high concentration. D. all of the above. ___

44. 44. Cells that do a lot of active transport have many _____. A. mitochondria B. nuclei C. chloroplasts D. plasmids ___

45. 45. The sodium-potassium pump, associated with muscle and nerve cells, moves Na+ to the outside of the cell and K+ to theinside of the cell. True False ___

46. 46. The functioning of the sodium-potassium pump depends upon the availability of ATP. True False ___

47. 47. Insulin leaves insulin-secreting cells by _____. A. phagocytosis B. receptor-mediated endocytosis C. osmosis D. exocytosis ___

48. 48. Macrophages, immune system cells, engulf bacteria by _____. A. exocytosis B. facilitated transport C. phagocytosis D. osmosis ___

49. 49. Specific molecules enter cells by _____. A. phagocytosis B. receptor mediated endocytosis C. diffusion D. osmosis ___

50. 50. The peptide hormone, follicle stimulating hormone, would activate its specific target cells by _____. A. diffusing into the cells B. binding a receptor protein in the plasma membranes C. phagocytosis ___