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43 Cards in this Set
- Front
- Back
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what are lipids
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biological molecules soluble in non polar solvents and insoluble in aqueous solutions
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what are the five lipid classifications?
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- fatty acids
- acylglycerols - phosphoacylglycerols - sphingolipids - steroids |
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fatty acids can be linked to glycerol to form
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acylglycerols and phosphoacylglycerols
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fatty acids can be linked to sphingosine to form
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sphingolipids
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fatty acids and steroids are made from what?
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acetyl CoA.
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how are fatty acids classified?
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- essential and non essential
- saturated and unsaturated |
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what are phosphoacylglycerols
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phospholipids with a glycerol backbone
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what are the three types of sphingolipids?
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ceramide, sphingomyelins, glycosphingolipids
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what are three types of steroids
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- cholesterol, steroid hormones, bile salts
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why would triacylglycerol break down into fatty acids?
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for energy
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fatty acids have a carboxylic acid moiety at one end. what happens to this carboxyl group at physiological pH?
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it is ionized, rendering a negative charge onto the FA.
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how many carbon atoms on a saturated FA makes them liquid at physiological temperature?
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less than 8
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FAs are solid with how many carbon atoms at physicological pH
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more than 10
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what significantly lowers the melting point of a FA?
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presence of double bonds
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what do you call a fatty acid with multiple double bonds?
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polyunsaturated fatty acids (PUFAs)
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why are fatty acids with double bonds packed less tightly? more fluid?
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because the double bond creates a kink
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naturally occurring unsaturated FAs have double bond in which configuration?
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cis
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trans FAs are used by restaurants. why?
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they have a longer shelf life
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what happens with excessive consumption of trans FAs
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increased risk for cardiovascular disease
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double bonds in polyunsaturated FAs are not conjugated and are generally separated by what?
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a methylene (-CH2-) group
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humans lack the ability to synthesize double bonds in unsaturated FAs beyond what position?
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delta (
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which two FAs are precursors to all other EFAs
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linoleic and alpha-linolenic acid
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how can EFAs with longer chains and greater degres of unsaturation be made?
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by enzymes on the cytoplasmic face of the ER
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how can animals make arachidonic acid?
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via injection of linoleic acid
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which FA is a precursor to prostaglandins and other related compounds like thromboxanes and leukotrienes?
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arachidonic acid
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what are compounds produced from arachidonic acid generally termed?
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eicosanoids
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why are compounds related to arachidonic acid important?
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they are regulators in cell-specific vital processes such as inflammation, vasodilation, vasoconstriction, bronchodilation, and blood clotting, etc
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which lipids are comprised of a glycerol backbone with one or more FAs liked via ester linkages?
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acylglycerols
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esterification of FAs with glycerol yields what? what catalyzes this rxn?
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acylglycerols
- catalyzed by acyltransferases |
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lipases catalyze the hydrolysis of what?
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acylglycerols
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triacylglycerol is the storage form of what?
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fat
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what are some examples of triaylglycerols?
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peanut oil, cottonseed oil, cod liver oil, bacon grease, lard
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what is the make up of a phosphoacylglycerol?
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2 FA acyl chains attached to carbon 1 and 2 and a phosphate or phosphate/alcohol to carbon 3 of the glycerol backbone
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how do you treat RDS (respiratory distress syndrome)
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- lung surfactant from cows
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in what month is lung surfactant produced in fetuses?
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6-7th months
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what are gangliosidoses and why is it bad?
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- lysosomal storage diseases associated with defective enzymes that process gangliosides
- leads to accumulation of gangliosides and cellular damage |
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- tay sachs is an example in which GM2 accumulates because of a defective what?
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hexoaminidase A
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what are symptoms of Tay Sachs?
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- usually at 6 months, mental retardation, cherry red spots on retina, psychomotor dysfunctions
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what is the most important steroid found in cells and tissues of higher organisms?
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- cholesterol
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where is cholesterol mainly synthesized?
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liver from acetyl coA
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what percentage of nerve cell membranes is cholesterol?
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about 25%
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how does cholesterol effect membrane fluidity?
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- decreases membrane fluidity
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what is cholesterol a precursor for?
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biles salts, steroid hormones, and vitamin D
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