Term
| Name the two components of a membrane. |
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Definition
| phospholipid and proteins |
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Term
| How are phospholipids arranged in the membrane? |
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Definition
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Term
| How are proteins arranged in the membrane? |
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Definition
| in patches throughout the phospholipid bilayer |
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Term
| State the term that means a membrane will only allow some molecules to pass through it. |
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Definition
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Term
| Give two features of passive transport. |
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Definition
| requires no energy, movement is from high to low concentration |
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Term
| Give two examples of passive transport. |
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Definition
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Term
| Describe diffusion across a cell membrane with one example. |
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Definition
| e.g. oxygen / glucose will diffuse into a cell; carbon dioxide will diffuse out of a cell |
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Term
| Give two ways that osmosis differs from diffusion. |
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Definition
| Osmosis involves only water, and it needs a selectively permeable membrane. |
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Term
| Describe the effect of placing red blood cells in water. |
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Definition
| water will eneter the cells and the red blood cells will swell up and burst |
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Term
| Describe the effect of placing red blood cells in a solution with a lower water concentration than the inside of the cell. |
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Definition
| water will leave the cell and the red blood cells will shrink |
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Term
| Under what circumstances will a plant cell become turgid? |
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Definition
| when plant cell is placed in solution of higher water concentration than the inside of the plant cell |
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Term
| What would cause a plant cell to become plasmolysed? |
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Definition
| when plant cell is placed in solution of lower water concentration than the inside of the plant cell |
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Term
| Describe the appearance of a plasmolysed plant cell. |
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Definition
| in a plasmolysed cell the membrane has been pulled away from the cell wall and the contents have shrunk |
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Term
| What do we call the movement of a substance against its concentration gradient? |
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Definition
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Term
| What moves the molecules or ions in active transport? |
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Definition
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Term
| What is required by the membrane proteins for active transport? |
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Definition
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Term
| What kind of substances are allowed to cross a selectively permeable membrane? |
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Definition
| small mollecules (e.g. glucose, oxygen, carbon dioxide, water) |
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Term
| What kind of substances are not allowed to cross a selectively permeable membrane? |
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Definition
| large molecules (e.g. starch, protein, fat) |
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Term
| How do you calculate a % change in mass? |
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Definition
| 1. calculate the change in mass 2. divide the change by the starting mass. 3. multiply the answer by 100 |
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Term
| How do you calculate an average? |
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Definition
| 1. add all the numbers in the list to get a total 2. divide the total by the number of numbers in the list |
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Term
| How can osmosis be used to find the concentration inside a cell? |
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Definition
| place the tissue in different concentrations and measure change in mass of the tissue, the concentration where there is no overall gain or loss of mass is equal to the concentration in the cells of he tissue |
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