BMBFIN P1L2*
C-2 epimers
Glucose and mannose
Amylose
alpha-1,4 glucan
Amylopectin
alpha-1,4 glucose chain with alpha-1,6 branching
O-glycosidic bond
A bond formed between the anomeric carbon of a sugar ring and an alcohol (this converts a hemi-acetal/ketal into an acetal/ketal, meaning the -OH becomes an -OR)
Fructose structure
6-carbon sugar with an electrophilic carbon on C2 (carbonyl carbon C1 moves over to C2 so that C1 is now CH2OH); ketoisomer of glucose (aldoketoisomerization); same structure as glucose except that the aldose is converted to a ketose
Furanose
A five-membered ring sugar
Pyranose
A six-membered ring sugar
Glucose structure
Aldose at top, CH2OH at bottom; 6 carbon pyranose ring forms; OH substituent on every carbon and they're ALL equitorial for beta-D-glucose (super stable; no steric hindrance); alpha-D-glucose is the anomer and C1 is axial. L-glucose can't form a ring (so no such thing as alpha- or beta-L-glucopyranose)
alpha- and beta- D-glucose are examples of...
Anomers
Galactose structure
C-4 epimer of glucose; all equitorial EXCEPT C4, which is axial
Mannose structure
C2 epimer of glucose; all equitorial EXCEPT C2, which is axial
Stereoisomers
Atoms connected in same order, but differ in spatial arrangement about one or more asymmetric or "chiral" carbons
What is the most abundant biomass on earth?
Cellulose
Glyceraldehyde and dihydroxyacetone are examples of...
Constitutional isomers
Ketoses
D-erythrulose and L-erythrulose
Most stable aldohexose
D-glucose
Aldoses example
D-glyceraldehyde and L-glyceraldehyde
Constitutional Isomers
Differ in atom connectivity (e.g. glyceraldehyde and dihydroxyacetone)
D-glucose and D-altrose are examples of...
Diastereomers
Epimers
Differ at only one of several chiral carbons (e.g. D-glucose and D-mannose)
Anomers
Differ at the chiral carbon formed on ring closure (e.g. alpha-D-glucose and beta-D-glucose)
D- and L- glyceraldehyde are examples of...
Enantiomers
D-glucose and D-mannose are examples of...
Epimers
Lactose structure
Galactose, glucose (beta-1,4 linkage)
C-4 epimers
Glucose and galactose
Sucrose structure
Glucose, fructose (alpha-1, beta-2 linkage)
Maltose structure
Glucose, glucose (alpha-1,4 linkage)
Fructose is the ____________ of glucose
Ketoisomer (aldoketoisomerization)
Examples of reducing sugars
Maltose and lactose
Starch
Mixture of two different "alpha-glucans", amylose (20-30%) and amylopectin (70-80%)
Ribose structure
Not even related to glucose; 5-carbon sugar (aldopentopyranose)
Glucan
Polysaccharide of D-glucose monomers
Isomers
Same molecular formula but different structures
Diastereomers
Stereoisomers: NOT mirror images (e.g. D-glucose and D-altrose)
Enantiomers
Stereoisomers: mirror images (e.g. D-glyceraldehyde and L-glyceraldehyde)
Example of a nonreducing sugar
Sucrose
Reducing sugars
Sugar rings that can reopen (exposing aldehyde/ketone carbonyl, which then can react) due to a slight instability of the hemi-acetal/ketal
Nonreducing sugars
Sugar rings that don't open because the o-glucosidic bond occurs between the anomeric carbons of two sugars so that both hemi-acetal/ketals are converted to acetal/ketals
Anomeric carbon
The new chiral center formed in ring closure; it was the carbon containing the carbonyl in the straight-chain form (from the ketone or aldehyde functional group)
Inulin
beta-1,2 fructose chain
Curdlan
beta-1,3 glucan
Lamarin (brown algae)
beta-1,3:beta-1,6 glucan
Cellulose
beta-1,4 glucan
Cellulose structure
beta-1,4 glucan (1-4 linkage; all equitorial) (most abundant biomass on earth)
Most prevalent fructose form in nature
beta-D-fructofuranose (C2-C5 five-membered sugar ring; "ketohexofuranose")
Most stable fructose form (in solution)
beta-D-fructofuranose (C2-C5 five-membered sugar ring; "ketohexofuranose")
Which molecule accounts for the majority of biomass on earth (e.g. plant starch and cellulose)
beta-D-glucose (because so stable!)
Most prevalent ribose form in nature
beta-D-ribofuranose (C2-C5 five-membered sugar ring; "aldopentofuranose" and a reducing sugar)
Most stable ribose form (in solution)
beta-D-ribopyranose (C1-C5 six-membered sugar ring with an axial OH on the 3rd carbon; "aldopentopyranose")
