| Transport Across Membranes |
| PowerPoint Questions |
Membrane Structure
1. Cell membranes of unicellular organisms are ____________ so the organism can move.
2. What is meant by homeostasis?
3. Homeostasis is also called __________________.
4. How does the plasma membrane help maintain homeostasis?
5. Give 7 functions of the plasma membrane.
a.
b.
c.
d.
e.
f.
g.
6. What is meant by the term selectively permeable?
7. What are cell junctions?
8. Fluid inside the cell is called _________________.
9. Label the plasma membrane (phospholipids, cholesterol, peripheral proteins, integral proteins, cytoskeleton, glcocalyx…)
10. A ________________ bilayer makes up most of the cell membrane.
11. Are phospholipids heads polar or nonpolar? the tails?
12. How many fatty acid chains are in a phospholipid?
13. Describe the heads of a phospholipid.
14. The __________ _____________ ___________ describes the appearance of the cell membrane.
15. Why is the cell membrane said to act like a fluid?
16. What causes the mosaic pattern of the cell membrane when viewed from above?
17. The phospholipid ____________ of the cell membrane allows ____________ molecules to pass through easily, but _________________ do NOT.
18. Materials soluble in __________ can pass easily through the cell membrane.
19. Because the cell membrane is ___________________, only ___________ molecules and larger _______________ molecules can move through easily.
20. List 3 substances that pass easily through the cell membrane.
21. _________, _____________ molecules larger than water, and large __________ molecules do NOT move easily through the phospholipids of the cell membrane.
Types of Membrane Transport
22. Simple ____________ requires NO energy to move things across the cell membrane.
23. With simple diffusion, molecules move from an area of ________ concentration to an area of ______ concentration.
24.Why is diffusion considered a passive process?
25. With diffusion, molecules move by their own natural __________ energy or energy of motion.
26. Explain what happens to a drop of food coloring put into a beaker of water.
27. When solutes diffuse through a membrane, they move from __________ to _________ concentration.
28. __________ is the diffusion of _________ across a cell membrane.
29. If water potential is HIGH, solute concentration is __________.
30. If water potential is LOW, solute concentration is ___________.
31. Water moves from _________ water potential to ________ water potential.
32. Water diffuses through the pores called _____________ of the cell membrane.
33. Sketch a picture of a cell in an isotonic environment & show the direction of water movement?
34. What is meant by NO NET movement?
35. Sketch a picture of a cell in an Hypotonic environment & show the direction of water movement?
36. Sketch a picture of a cell in an hypertonic environment & show the direction of water movement?
37. Complete the following table:
| Direction of Osmosis | ||
| Environmental Condition | Net Movement of water | What happens to cell |
| Hypotonic | ||
| Hypertonic | ||
| Isotonic | ||
38. _____________ occurs whenever water moves out of a cell & the cell shrinks in size.
39. _____________ occurs whenever water moves into the cells causing them to swell and burst.
40. Explain what happens to a red blood cell placed in:
a. distilled water
b. a concentrated salt solution
41. Complete the following drawings.
42. Plants prefer ________________ environments, while animal cells do best in _____________ environments.
43. Describe these 3 types of movement across cell membranes.
a. simple diffusion
b. facilitated diffusion
c. active transport
44. Passive transport does _______ require additional energy & moves materials from ________ to _________ concentration.
45. Give 2 examples of passive transport in cells.
46. ___________ diffusion is a type of __________ transport because energy is NOT required.
47. Facilitated diffusion uses _____________ proteins to help move materials from _________ to __________ concentrations.
48. Name 2 materials that move into or out of cells by facilitated diffusion.
49. name 2 types of transport proteins found in cell membranes.
50. Describe channel proteins.
51. How do carrier proteins help move materials across a cell membrane?
52. Channel proteins have an opening or ___________ through which molecules can passively move by _____________ diffusion.
53. Do all carrier proteins extend across the cell membrane?
54. Explain how these carrier proteins move materials across the membrane.
55. Some carrier proteins can change ________ to move materials across the cell membrane.
56. __________ transport requires additional energy to move materials.
57. Active transport uses cellular energy known as _________.
58. Active transport moves materials AGAINST the concentration gradient or from _________ to ___________ concentration.
59. The _______________ pump is an example of active transport.
60. The sodium-potassium pump moves _______ sodium ions out for every ______ potassium ions moved into the cell creating voltage across the cell called the ____________ potential.
61. Moving very large particles out of the cell is called _____________.
62. In exocytosis, wastes are moved out of the cell in ___________ that fuse with the cell membrane.
63. __________ involves moving large particles into the cell.
64. taking in large liquid droplets is called ____________ or “cell drinking”.
65. __________ ____________ endocytosis involves protein ____________ recognizing hormones to help move them into the cell.
66. How does cholesterol get into a cell?
67. “Cell eating” is known as ______________.
68. White blood cells engulfing bacteria is an example of _____________.
69. _____________ is the opposite of exocytosis.
