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13 Cards in this Set
- Front
- Back
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through which organelle does diffusion occur? |
the cell membrane |
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give an example of osmosis, the diffusion of water only through a membrane |
if you put a raisin in water, the water will soak through the raisin's outside, and turn squishy, having water inside the raisin -- the raisins outside is like a cell membrane |
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how does a semipermeable membrane help with diffusion? |
semipermeable membranes have pores to let some molecules through |
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what is equilibrium? |
when the concentration of a substance is equal on each side of the membrane |
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through which process of diffusion are transport proteins needed? |
facilitated diffusion - when molecules are too large to fit through the membrane |
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what are the two kinds of transport proteins, and what are their purposes? |
carrier protein - carry large molecules through the membrane channel protein - form large pores through the membrane for atomic particles |
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what is the difference between passive transport and active transport? |
passive transport - moves molecules from high to low concentration, does not use energy active transport - moves molecules from low to high concentration, does use energy |
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why is active transport so important for cells and organelles? |
cells take in needed nutrients from the environment through carrier proteins, and some other molecules and waste materials leave cells by active transport |
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what is the point of endocytosis and exocytosis? |
some substances are too large to enter a membrane by using diffusion or a transport protein |
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when endocytosis occurs, what happens to the molecule entering the cell? |
the molecule merges into the cell and pushes through to create a vesicle in side the cell (part of the membrane now around it) |
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when exocytosis occurs, what happens to the molecule entering the cell? |
the vesicle merges into the cell and pushes through to release the molecule outside of the cell |
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as a cell grows, does the volume or the surface area of the cell grow faster? |
the volume |
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true or false, the surface area of a cell must be large compared the the volume |
true |
