Transport Across Membranes
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.
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|
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.