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38 Cards in this Set
- Front
- Back
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monosaccharides
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simplest carbs
aldehydes or ketones that have 2 or more hydroxyl groups (C-H2O)n |
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3 smallest monosaccharides
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ketose: dihydroxyacetone
aldoses: D-glyceraldehyde, L-glyceraldehyde |
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epimers
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sugars differing at 1 asymmetric center (i.e. D-glucose/D-mannose)
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D-erythrose
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aldose just larger than D-glyceraldehyde--4Cs
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D-ribose
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epimer of D-arabinose
5C aldose |
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D-glucose
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6C aldose
OH HO OH OH epimer of D-mannose |
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D-mannose
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epimer of D-glucose
6C aldose HO HO OH OH |
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D-galactose
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6C aldose
OH HO HO OH |
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which stereocenter determines D or L label on aldoses?
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stereocenter furthest from aldehyde or ketone
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D-erythrulose
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4C ketose
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D-ribulose
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5C ketose
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D-fructose
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6C ketose
epimer of D-psicose |
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aldehydes react with an alcohol to form____________
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hemiacetal (when aldoses form rings)
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ketones react with an alcohol to form _________________
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hemiketal (when ketoses form rings)
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5-sided sugar
6-sided sugar |
furanose (five)
pyranose (six) |
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when OH to the right of O in a pyranose or furanose is below the plane of the ring
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alpha
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when OH to the right of O in a pyranose or furanose is above the plane of the ring
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beta
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sugar phosphorylation does what 2 things?
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1) makes sugars anionic--negative charge means sugars can't cross lipid bilayer membrane
2) creates reactive intermediate--readily form linkages to other molecules |
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oligosaccharides
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links of monomers built by linkage of O-glyosidic bonds
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sucrose
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disaccharide
transport carb in plants glucose (alpha linkage) and fructose (beta linkage) |
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lactose
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disaccharide of milk
galactose and glucose (beta 1,4 linkage) |
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maltose
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disaccharide produced by hydrolysis of starch
2 glucose (alpha 1,4 linkage) |
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3 disaccharides
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maltose, lactose, sucrose
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glycogen
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large, branched polymer of glucose residues
most are in alpha 1,4 glycosidic bonds form hollow helixes |
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2 forms of starch
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amylose--unbranched glucose residues in alpha 1,4 linkages
amylopectine--branched |
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cellulose
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structural polymer of plants
unbranched polymer of glucose residues joined by beta 1,4 linkages |
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fibrils
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parallel chains of cellulose that interact through H-bonds
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glycosaminoglycans
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anionic polysaccharide chains made up of repeating disaccharide units (have proteoglycans attached)
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proteoglycans
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proteins attached to glycosaminoglycans
function as joint lubricants and structural components in connective tissue |
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5 major glycosaminoglycans in animals
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chondroitin 6-sulfate, keratin sulfate, heparin, dermatan sulfate, hyaluronate
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aggrecan
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proteoglycan in extracellular matrix of cartilage
serves as shock absorber noncovalently bonded to hyaluronan strands that have proteoglycan arms that absorb water and cushion joints |
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glycosyltransferases
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catalyze formation of glycosidic bonds that link monosaccharides
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A,B and O blood types
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carbohydrates are attached to proteins and lipids on surface of red blood cells
O=oligosaccharide foundation A and B made by addition of an extra monosaccharide by an alpha 1,3 linkage to galactose moiety on O A=N-acetylgalactosamine B=galactose specific glycosyltransferases add A or B to O |
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sugars in glycoproteins are either attached to...
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N in side chain of Asn or O in Ser or Thr
an Asn residue can only accept an oligosaccharide if residue is part of Asn-X-Thr or Asn-X-Ser (x can be anything except proline) |
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glycoprotein
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protein with carbohydrate attached by glycosidic bonds
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glycosyl transferases are found in
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the ER and golgi
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lectins
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bind specific carbohydrate structures on opposing cell
some lectins require Ca++ which acts as a bridge between protein and sugar |
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H1N1 and carbohydrates
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H1N1 binds to carbs on surface of cell
viral protein hemagglutinin binds to sialic acid residues on cell-surface glycoproteins after entry into cell, neuraminidase cleaves glycosidic bond to sialic acid |
