Term
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Definition
most simple
molecules don't become concentrated on either side
flows with concentration gradient
no carrier molecules |
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Term
| carrier mediated diffusion |
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Definition
transported molecules helped by "receptor proteins" or "carriers" that can bind to the molecule
no energy required
transport occurs WITH concentration gradient |
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Term
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Definition
| transport two different substances in opposite directions |
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Term
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Definition
| transport one substance in one direction |
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Term
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Definition
| transport two different substances in the same direction |
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Term
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Definition
no energy req
with concentration gradient
no membrane protein required
not specific |
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Term
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Definition
no energy required
with concentration gradient
membrane protein required
specific |
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Term
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Definition
energy required
ATP hydrolysis (against concentration gradient)
membrane protein required
specific |
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Term
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Definition
the process by which complex molecules and large particles, bacterial cells, and water can enter cells
membrane vesicle is brought into the cell |
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Term
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Definition
| large particles and small cells are engulfed into the lumen of the vesicle; type of endocytosis |
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Term
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Definition
| "cell drinking" cells take up water into vesicles; type of endocytosis |
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Term
| receptor-mediated endocytosis |
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Definition
specialized form of endocytosis for taking certain kinds of macromolecules into cells;
first - macromolecule binds to specific receptor on cell surface forming a "coated pit"
protein clathrin coats the inside surface of the plasma membrane
clathrin - coated vesicle forms around the macromolecule
vesicle moves into the cell cytoplasm and becomes uncoated - releasing its contents |
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Term
| LDL Endocytosis and Atherosclerosis |
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Definition
LDL particle binds to LDL receptor @ cell surface leading to formation of coated pit
LDL particle taken up into clathrin coated vesicles
vesicle uncoats
vesicle fuses with lysosome which digests contents of vesicle-releasing the cholesterol which then is inserted into plasma membrane |
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Term
| defects in the regulated uptake of LDL particles causes |
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Definition
hypercholesterolemia; buildup of cholesterol in blood plasma
deposition of cholesterol on artery walls (artherosclerosis)
one defect leading to hypercholesteremia is genetically determined absence of the LDL receptor |
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Term
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Definition
processes by which complex molecules packed into vesicles in cells fuse with plasma membrane and are dumped out of cells
secretory vesicle inside cell fuses with the plasma membrane
vesicle contents dumped out |
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Term
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Definition
link cells together VERY TIGHTLY
don't allow passage of materials in space between two cells
don't allow movement of membrane proteins inside the membrane itself |
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Term
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Definition
allows space between cells
doesn't limit movement in space between cells |
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Term
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Definition
permits passage of large molecules between two cells
made of connexons |
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