3.12: Diffusion and Osmosis Worksheet Answers
1. List 5 mechanisms by which molecules pass through the plasma membrane. State whether these mechanisms are passive or active (ie use energy or not).
|
Mechanism for crossing
plasma membrane |
Passive or Active? |
|---|---|
| 1. Diffusion | Passive |
| 2. Facilitated diffusion | Passive |
| 3. Osmosis | Passive |
| 4. Active transport | Active |
| 5. Pinocytosis/phagocytosis/exocytosis | Active |
2. Which mechanism:
- a.) uses no energy and results in an even distribution of molecules? Diffusion
- b) uses no energy, and occurs across a semi-permeable membrane? Osmosis
- c) occurs across the membrane of red blood cells causing them to swell and burst when placed in distilled water? Osmosis
- d) uses energy and allows the cell to take into itself particles and bacteria? Phagocytosis
- e) moves substances across the plasma membrane from a low to a high concentration? Active transport
- f) uses a carrier molecule to help substances across a membrane but does not require energy? Facilitated diffusion
3. Circle the correct statements below.
Diffusion is a process that:
- a) occurs in liquid and gases
- d) uses no energy
- e) occurs naturally
- g) occurs from a higher concentration of molecules to a lower one .
- h) results in an even distribution of molecules
- k) is more rapid at high tempera tures.
4. Circle the correct statements below.
Osmosis :
- a) is a special kind of diffusion .
- d) is the diffusion of water molecules only .
- e) is the diffusion of water molecules from a high concentration of water to a low concentration of water .
- f) requires a semi-permeable membrane .
- h) results in an even dispersal of water molecules .
5. A semi-permeable membrane is a membrane that:
- a) allows some molecules to go through but not others .
6. Active transport :
- a) uses energy .
- c) occurs from a lower concentration of molecules to a higher concentration .
7. Oxygen crosses the plasma membrane by:
- c) diffusion through the lipid bilayer .
8. Water crosses the plasma membrane by:
- e) osmosis .
9. Lipid soluble molecules cross the plasma membrane by:
- c) diffusion through the lipid bilayer .
10 Sodium ions move from a low to a high concentration across the plasma membrane by:
- b) active transport .
11 Glucose molecules cross the plasma membrane by:
d) facilitated diffusion .