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35 Cards in this Set
- Front
- Back
fluid mosaic model |
accounts for the presence of lipids, proteins and carbohydrates in a dynamic, semisolid plasma membrane that surrounds cells |
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lipid rafts |
collections of similar lipids with or without associated proteins that serve as attachment points for other biomolecules; serve roles in signaling |
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flippases |
specific membrane proteins that maintain the bidirectional transport of lipids between the layers of the phospholipid bilayer in cells |
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triacylglycerols and free fatty acids |
act as phospholipid precursors and are found in low levels in the membrane |
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glycerophospholipids |
replace one fatty acid with a phosphate molecule, which is often linked to other hydrophilic groups |
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cholesterol |
present in large amounts and contributes to membrane fluidity and stability provides membrane fluidity by interfering with the crystal structure of the cell membrane and occupying space between phospholipid molecules provides stability by cross-linking adjacent phospholipids through interactions at the polar head group and hydrophobic interactions at the nearby fatty acid tail |
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waxes |
present in very small amounts, if at all; they are most prevalent in plants and function in waterproofing and defense |
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proteins located within the cell membrane act as |
transporters, cell adhesion molecules and enzymes |
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transmembrane proteins |
can have one or more hydrophobic domains and are most likely to function as receptors or channels |
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embedded proteins |
most likely to be a part of a catalytic complex or involved in cellular communication (in other words, most likely to have catalytic activity linked to nearby enzymes) |
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membrane-associated (peripheral) proteins |
may act as recognition molecules or enzymes on the extracellular surface and be involved in signaling |
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carbohydrates |
can form a protective glycoprotein coat and also function in cell recognition |
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membrane receptors |
bind extracellular ligands and function as channels or enzymes in second messenger pathways |
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cell-cell junctions |
regulate transport intracellularly and intracellularly include: gap junctions tight junctions desmosomes |
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gap junctions |
allow for the rapid exchange of ions and other small molecules between adjacent cells do not prevent paracellular transport of materials found in discontinuous bunches around the cell |
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tight junctions |
prevent paracellular transport, but do not provide intercellular transport form bands around the cell |
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desmosomes and hemidesmosomes |
anchor layers of epithelial tissue |
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osmotic pressure |
a colligative property the pressure applied to a pure solvent to prevent osmosis and is used to express the concentration of the solution better conceptualized as a "sucking" pressure in which a solution is drawing water in, proportional to its concentration |
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passive transport |
does not require energy because the molecule is moving down its concentration gradient or from an area with higher concentration to an area with lower concentration includes: simple diffusion osmosis facilitated diffusion |
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simple diffusion |
does not require a transporter small, nonpolar molecules passively move from an area of high concentration to an area of low concentration until equilibrium is achieved |
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osmosis |
describes the diffusion of water across a selectively permeable membrane |
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facilitated diffusion |
uses transport proteins to move impermeable solutes across the cell membrane |
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active transport |
requires energy in the form of ATP or an existing favorable ion gradient includes: primary and secondary active transport |
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primary active transport |
uses ATP or another energy molecule to directly transport molecules across a membrane |
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secondary active transport (or coupled transport) |
harnesses the energy released by one particle going down its electrochemical gradient to drive a different particle up its gradient includes: symport antiport |
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symport |
type of secondary active transport in which the particles flow in the same direction across the membrane |
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antiport |
type of secondary active transport in which the particles flow in opposite directions across the membrane |
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pinocytosis |
the ingestion of liquid into the cell from vesicles formed from the cell membrane |
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phagocytosis |
the ingestion of bacteria by phagocytes |
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membrane potential |
maintained by the sodium-potassium pump and leak channels |
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Nernst equation |
used to calculate the electrical potential created by one ion |
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Goldman-Hodgkin-Katz voltage equation |
derived from the Nernst equation and used to calculate the resting potential of a membrane at physiological temperature |
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outer mitochondrial membrane |
highly permeable to metabolic molecules and small proteins |
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inner mitochondrial membrane |
surrounds the mitochondrial matrix, where the citric acid cycle produces electrons used in the electron transport chain and where many other enzymes important in cellular respiration are located does not contain cholesterol |
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examples of sphingolipids |
gangliosides ceramide sphingomyelin cerebrosides sphingolipids |