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Carbohydrate - Coggle Diagram
Carbohydrate
properties
are a mechanism of energy storage
most abundant of world's biomass and are mostly made through photosynthesis by plants
have structural roles and can be part of drugs
what molecules they can be part of
glycoproteins
proteins with SHORT carbohydrate branches
found in receptors/recognition
proteoglycans
proteins with LONG carbohydrates
in connective tissue and cartilage
peptidoglycans
long carbohydrates crosslinked by short oligopeptides
in bacterial cell walls
lipopolysaccharides
fatty acid attached to carbohydrate
in outer layer of gram-negative bacteria
classifying and representing
1 monosaccharide of a carbohydrate is a carbohydrate that cannot be further hydrolyzed
classification
classified by number of carbons + the suffix "ose"
if carbonyl group is present
it is called an aldose if an aldehyde group is present
it is called a ketose if a ketone group is present
the prefix keto can be dropped for the suffix ulose instead
representation
the smallest monosaccharide is a triose
the 2 that exist which are an aldose and a ketose
in Fischer projection, they are drawn such that the CHO is on top and the rest of the chain is on the bottom
from this, can determine D/L using the furthest carbon from carbonyl group
D has the OH on the right
rotates light to the right
first determined based on guessing but was later proved by x-ray crystallography
only chiral centers can rotate light and enantiomers rotate light in opposite directions but same magnitude
There is no correlation between D/L and the direction (+/-) of rotated light
1 more item...
L has the OH on the left
rotates polarized light to the left
D/L refers to the carbohydrate's ability to rotate plane polarized light
D/L shows the molecules are enantiomers
carbohydrates are organized based on their OH arrangement pattern
different carbs with diff common names are diastereomers
with each new C in a carbohydrate chain, we double the number of stereoisomers
for ketoses, we only start getting diastereomers at 4 C
modified monosacchrides
x-deoxy at position x means an OH is removed here
if another group follows at that position, that means this group goes to where the Oh was
glucuronic acid indicates the last carbon is modified to a COOH
formation of hemiacetals
formed through a intermolecular reaction between the hydroxyl of the penultimate carbon and the carbonyl
forms a 5 C ring (furanose)
forms a 6 C ring (pyranose)
drawing the Hayworth projection
rotate sugar on side
draw the backbone
add the OH according to the orientation of the rotated sugar on side
CH2OH goes up in D sugar because the CH2OH group is higher than the OH in the side projection
CH2OH goes down in L sugar because the CH2OH group is lower than the OH in the side projection
the anomeric carbon
it is an sp2 carbonyl that can freely rotate
the pneultimate C can attack from above or below, creating an alpha or beta anomer
they are diastereomers
alpha have the OH and CH2OH on diff sides
beta has OH and CH2OH on same side
due to the reversibility of hemiacetal formation, anomers can interconvert in aq. solution
2 more items...
drawing ketose Hayworth projection
rotate sugar on side
draw backbone from pneultimate carbon to the carbonyl of the ketose ( 5 C ring)
the double bond here becomes a single bond
formation of glycosides
forms an OME from and OH
uses another alcohol to form product through an acid-catalyzed SN1 rxn
no matter if the starting hemiacetal is alpha or beta, we always get a mixture of alpha and beta glycosides