1. Movement In and Out of Cells
Chapter 2
1. Diffusion
2. Osmosis
3. Active Transport

2. 1. Diffusion
The net movement of molecules from a region of their higher concentration to a region of their lower concentration along a concentration gradient, as a result of their random movement.
When they can move freely, particles tend to spread themselves out as evenly as possible.
Examples:
Plant cells: Gas exchange
Plant cells: Flowers
Animal cells: Gas exchange
Animal cells: Digestion
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3. Example: Plant Cell-Gas ExchangeLC HC HC LC
Carbon dioxide diffuses into the leaves through the stomata from a high concentration to a low concentration along the concentration gradient.
Oxygen diffuses out of the leaves through the stomata from a high concentration to a low concentration along the concentration gradient. 1.

4. Example: Plant Cell-FlowersLC HC HC LC
The scent from flowers diffuse from a high concentration to a low concentration along the concentration gradient into the air around them, which stimulate receptors in the bee’s body. 1.

5. Example: Animal Cell-Gas ExchangeHC HC LC LC HC HC LC
Oxygen diffuses into of the cell from a high concentration to a low concentration along the concentration gradient.
Carbon dioxide diffuses out of the cell from a high concentration to a low concentration along the concentration gradient. 1.

6. Example: Animal Cell-DigestionHC LC LC LC
Food diffuses out of the ileum (small intestine) during digestion from a high concentration to a low concentration along the concentration gradient. 1.

7. 2. Osmosis
The diffusion of water molecules from a region of their higher concentration (dilute solution) to a region of their lower concentration (concentrated solution), through a partially permeable membrane.
The diffusion of water molecules from a region of their high water potential to a region of their low water potential, along the water potential gradient.
Dilute Solution: high water potential:
More solvent (water)
Less solute (sugar/salt)
Concentrated Solution: low water potential:
Less solvent (water)
More solute (sugar/salt)
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Animal cell: Dilute solution
Plant cell: Dilute solution
Animal cell: Concentrated solution
Plant cell: Concentrated solution

8. Osmosis in Animal Cells: Dilute solution
Dilute solution: pure water: high concentration
Concentrated solution: cytoplasm: low concentration
More concentrated solution inside the cytoplasm
Less concentrated solution in the pure water
Water diffuses into the cell through the partially permeable cell surface membrane.
Water diffuses from a high concentration (dilute solution: pure water) to a low concentration (concentrated solution: cytoplasm) along the concentration gradient through the partially permeable cell surface membrane 2.

9. Osmosis in Animal Cells: Concentrated solution
Dilute solution: cytoplasm: high concentration
Concentrated solution: outside cytoplasm: low concentration
Water diffuses out of the cell through the partially permeable cell surface membrane.
Water diffuses from a high concentration (dilute solution: cytoplasm) to a low concentration (concentrated solution: outside cytoplasm) along the concentration gradient through the partially permeable cell surface membrane 2.

10. Osmosis in Plant Cells: Dilute solution
Dilute solution: pure water: high concentration
Concentrated solution: cytoplasm: low concentration
More concentrated solution inside the cytoplasm
Less concentrated solution in the pure water
Water diffuses into the cell through the partially permeable cell surface membrane.
Water diffuses from a high concentration (dilute solution: pure water) to a low concentration (concentrated solution: cytoplasm) along the concentration gradient through the partially permeable cell surface membrane
The cell swells and becomes turgid. 2.

11. Osmosis in Plant Cells: Concentrated solution
Dilute solution: cytoplasm: high concentration
Concentrated solution: outside cytoplasm: low concentration
Water diffuses into the cell through the partially permeable cell surface membrane.
Water diffuses from a high concentration (dilute solution: cytoplasm to a low concentration (concentrated solution: outside cytoplasm) along the concentration gradient through the partially permeable cell surface membrane
The cell shrinks and becomes flaccid.
The cell plasmolysis: the cell membrane detaches from the cell wall. 2.

12. 3. Active Transport
The movement of ions in or out of a cell through a cell membrane, from a region of their lower concentration o a region of their lower concentration against their concentration gradient, using energy released during respiration.
Cell membranes contain carrier proteins
Active Transport in Plants
Active Transport in Animals
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13. Active Transport: Root hair cells
Vacuole
soil particles
Cell membrane with cell wall
Minerals and Water absorbed
The movement of nitrate ions into a root hair cell through the cell membrane, from a region of their lower concentration to a region of their higher concentration against their concentration gradient, using energy released during respiration. 3.

14. Active Transport: Small intestine
The movement of glucose into cells of villi through the cell membrane, from a region of their lower concentration to a region of their higher concentration against their concentration gradient, using energy released during respiration. 3.