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6 Cards in this Set
- Front
- Back
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What is diffusion? |
The spreading of particles of a substance insolution or a gas which results in a movement from a regionwhere there is a higher concentration to one where there is a lower concentration The greater the difference in concentration, the faster the rate of diffusion |
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Where is diffusion used in the body? |
Dissolved substances move into and out of cells by diffusion Oxygen required for respiration passes through cell membranes by diffusion |
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What is osmosis? |
The diffusion of water from a dilute to a more concentratedsolution through a partially permeable membrane Differences in the concentrations of the solutions inside and outside acell cause water to move into or out of the cell by osmosis |
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What are the terms associated with diffusion and osmosis? |
Isotonic - solution of osmotic pressure is equal to another solution Hypotonic - less osmotic pressure in one solution than another
Hypertonic - higher osmotic pressure in one solution than the other Turgid - cell is filled with water; it is firm Flaccid - cell is floppy and wilting Plasmolysis - cell membrane wilts due to lack of water Cytoclosis - the process of which cells gain water in a hypotonic solution |
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What is active transport? |
When substances are absorbed against a concentration gradient using energy from respiration It enables plants to absorb ions from very dilute solutions Sugar may be absorbed from low concentrations in the intestine and the kidney tubules |
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A single-celled organism has a relatively large surface area to volume ratio All the necessary exchanges occur via its surface membrane The size and complexity of an organism increase the difficulty of exchanging materials |
