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35 Cards in this Set
- Front
- Back
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Nomenclature
Carbohydrates are hydrates of carbon |
monosacc: are simplest form
oligo: 2-10 monos polysacc: polymers of simple sugars |
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Monosaccharides
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tri/tetr/pent-ose denote C#
aldoses with 3> or ketoses with 4> C's are chiral |
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aldose
ketose |
glyceraldehyde: H-C=O
dihydroxyacetone: C=O |
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Stereochemistry with D and L
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Refers to configuration of the highest-#ed asymmetric center
D-sugars are predominate |
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purpose of D and L configurations
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Galactosemia: failure to convert galactose to glucose results in accumulation of Gal in blood stream which causes cirrhosis and retardation
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enantiomers of mirror image configurations
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only in the middle of molecule switching the OH and H attached to parent C strand
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aldopentoses
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ribose, xylose
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aldohexoses
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glucose, galactose, mannose
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ketopentoses
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ribulose, xylulose
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ketohexoses
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fructose
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Cyclic monosacc and anomeric forms
(alcohol) glu, fru, aldohex, ketohex |
glu:(aldose) hemiacetal
fru:(ketose)hemiketal aldohex: form pyranose ketohex: form furanose |
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Haworth projections
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draws sugars, represent pyranose and furanose as hex and pent rings perpendicular to the plane of the paper.
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Fischer to haworth
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left:above ring
right:below ring Haworth alpha:OH below ring(both for D)beta:OH above ring |
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beta-D-fructofuranose
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linear form of D-fructose undergoes intramolecular rxn to from a cyclic hemiketal.
C5-OH attacks C2=O |
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anomers
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cyclization of sugars creates one more chiral center that is the anomeric C, conversion of C=O to C-OH
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anomeric C continued
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OH group in the anomeric C may be alpha or beta
For D-sugars, alpha has OH down and beta's is up |
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Chair and boat conformations
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chair is 109 degrees
equatorial: coplanar with ring axial: parallel to axis |
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rules of chair and boat
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chair are more stable
bulky R groups on rings most likely fill equatorial positions |
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Monosaccharide derivitives
(reducing sugars) glucose is one, basis for diagnostic tests for blood sugar |
sugars with free anomeric C's:will reduce oxidizing agents like peroxide.The redox rxns convert sugar to acid
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More derivitives:
sugar alcohols deoxy sugars sugar esters |
alc: mild reduction
deoxy: DNA constituents amino: amino instead of OH |
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sugar alcohols
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linear, dont cyclize, sweet
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deoxy sugars
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one or more OH replaced by H
occur in glycoproteins |
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sugar esters
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metabolic intermediate
complete P and O, R group |
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amino sugars
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amino instead of OH at C2
oligosacc and polysacc |
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Beta-D-glucosamine
Beta-D-galactosamine |
glu:H up
gal:H down both have NH2 parallel to O |
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ketal to hemiketal
(both reversible) Acetal to hemiacetal |
4R groups + H2O--> 3R + R-OH
3R + H2O--> 2R + R-OH |
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Oligosaccharides
OH above=beta (visa versa) HOH:free anomeric C (reducing end) |
sucrose is NOT a reducing sugar
alpha 1,4: glycosidic is bent beta 1,4: straight/stretched |
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Common disaccharides
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lac: gal-B-1,4-Glc....milk
su: Glc-A-1,2-Fru....plants malt:Glc-A-1,4-Glc celluobiose: Glc-B-1,4-Glc |
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Polysacchardides=Glycans
(functions: store, structure and recognition) |
polymers of monosacc & deriv's
starch,glycogen: storage chitin, cellulose: structure surface polysacc: recognition |
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Starch
(amylose has alpha (1,4), one reducing end and alpha (1,6) |
2 forms:amylose & amylopectin
10-30% amylose (linear) 70-90% amylopectin |
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Glycogen
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constitutes 10% liver mass and 1-2% muscle mass
diff from starch: # branches alpha(1,6) branches every 8-12 residues like amylopectin is red-violet with iodine |
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Structural Polysaccharides
(similar to storage polysacc) |
cellulose:most abundant natural polymer on earth, principle strength of trees
(has beta complex, linear) |
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Chitin
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exoskeletons of crustaceans, insects and spiders, cell walls of fungi.
similar to cellulose but C2's are N-acetyl can be parallel or anti |
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glycosaminoglycans
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repeating disacc with amino sugars and (-) charges
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glycoproteins
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O-link sacc:mannose, galact, xylose
N-link: mannose triad |
