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Description
Flashcards by Clare Noone, updated more than 1 year ago
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Created by Clare Noone
over 6 years ago
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| Question | Answer |
| What is diffusion? | Diffusion is the spreading out of particles from an area of a higher concentration to an area of lower concentration. This will process will be faster with a higher temp and high concentration gradient |
| Name three substances that can diffuse through cell membranes, and two that can't: | CAN: dissolved substances, small molecules(oxygen, glucose etc), particles CANNOT: big molecules (starch/proteins) |
| What is osmosis? | The movement of water molecules across a partially permeable membrane from a region of higher water concentration to a lower water concentration. |
| What is Active transport? | Active transport is the process by which dissolved molecules move across a cell membrane from a lower to a higher concentration. In active transport, particles move against the concentration gradient - and therefore require an input of energy from the cell |
| Give 3 adaptations of exchange surfaces that increase the efficiency of diffusion: | thin membrane- short distance to diffuse large surface area- lots of it at once lots of blood vessels- into blood quickly gas exchange surfaces are often ventilated meaning air moves in and out |
| How are villi in the smol intestine adapted? | increased surface area, single layer of surface cells (short distance to diffuse substances), good blood supply |
| How are leaves adapted for the retrieval of carbon dioxide? | flattened shape means an increase in surface area, air spaces inside mean more chance for carbon dioxide to get into the cells |
| How are gills adapted? | good blood supply, gill filaments create a larger surface area and smaller lamellae do too, thin surface layer |
| How are alveoli adapted? | large surface area, moist lining for dissolving gases, thin walls, good blood cells |
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