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37 Cards in this Set
- Front
- Back
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what does allosteric regulation mean |
all enzymes capable of allosteric regulation exist in two different forms (allosteric means another shape or form) |
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enzyme that can exist in a high substrate affinity form or a low-none substrate affinity form
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allosteric enzyme |
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this type of inhibitor binds covalently to an enzyme resulting in permanent loss of catalytic activity
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irreversible inhibitor |
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both substrate and inhibitor bind share the same active site |
competitive inhibition |
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inhibitor and substrate have different active sites |
non-competitive inhibition |
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regulation that depends directly on the interactions between substrate and products with an enzyme |
substrate- level regulation |
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when the product is a specific inhibitor to the enzyme that catalyzes the reaction |
feedback inhibition |
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the conformational changes that affect the affinity of a binding site an enzyme undergoes as a result of catalytic activity |
cooperativity |
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form of enzyme modification where an enzymes activity is affected by adding or removing chemical groups via covalent bonding |
covalent modification |
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addition of a phosphoryl group |
phosphorylation |
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enzymes that catalyze the phosphorylation of other proteins or enzymes |
protein kinases |
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removal of a phosphoryl group |
dephosphorylation |
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enzymes that remove phosphoryl groups |
protein phosphatases |
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the arrow from left to right shows _ while the arrow from right to left shows _ |
1) phosphorylation 2) dephosphorylation |
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covalent activation of enzymes by irreversible removal of a portion of the polypeptide chain |
proteolytic cleavage |
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catalytically inactive enzyme that must be cleaved proteolytically to be activated |
zymogens |
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What are the functions of biological membranes? |
1) define boundaries and act as permeability barriers 2)sites for specific biological biochemical functions ex. electron transport or protein processing 3) have transport proteins to regulate movement in and out of cell 4) contain protein molecules to detect extracellular signals 5) provide mechanisms for cell to cell interactions |
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the permeability barrier of a cell |
plasma membrane |
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main membrane classes of lipids |
phosholipids, glycolipids and sterols |
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saturated fatty acid is different than a unsaturated fatty acid in what way? |
the carbons in a saturated fatty acid are bonded to the maximum amount of hydrogens possible. in unsaturated fatty acids there are double bonds
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why are fatty acids important to membranes? |
because their large hydrocarbon tails form a strong hydrophobic barrier |
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what are the three kinds of phospholipid movements within a membrane |
flipflop/ tranverse diffusion, rotation and lateral diffusion |
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what two properties of a membrane fatty acid composition affect fluidity |
degree of saturation and length of fatty acid chain |
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Assuming the temperature is the same, which membrane will be more fluid? A) 20 chain fatty acid B)10 chain fatty acid |
10 chain |
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which fatty acid chain will be more fluid? A) no double bonds (saturated) B) 2 double bonds (unsaturated) |
B |
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how do sterols affect fluidity in a membrane? |
sterols make the membrane more fluid at temperatures below the transition temp and more gel-like at temperatures above the transition temp |
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besides fluidity what else do sterols do for the membrane? |
make them less permeable to ions and small molecules |
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amphipathic molecules having an affinity for the lipid bi layer |
intergral membrane proteins |
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membrane protein that protrudes out one side of the membrane |
integral monotopic protein |
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protein that crosses the membrane/ protrudes out both sides, can be multi or single pass |
transmembrane protein |
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anchors the transmembrane protein
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transmembrane segment |
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4 kinds of integral membrane proteins |
1)integral monotopic protein 2) singlepass protein 3) multisubunit protein 4)multipass protein |
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proteins bound to the membrane |
peripheral membrane proteins |
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what forces keep peripheral membrane proteins bound? |
hydrogen bonding and weak electrostatic forces |
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what forces keep lipid anchored proteins bound? |
covalent bonds |
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what are the two kinds of lipid anchored proteins? |
1)glycophosphatidylinositol (GPI) anchor 2)fatty acid/ isophrenly anchored |
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what are the two ways membrane proteins move? |
1) freely 2) anchored/ don't move |
