Carbohydrates Flashcards
define: carbohydrates
polyhydroxyaldehydes/polyhydroxyketones, or form these compounds upon hydrolysis
define: monosaccharides
carbs that cant be hydrolysed to a simpler form.
how do you name monosaccs
prefix: meth eth tri tetr pent ..
suffix: ose
aldo/keto prefix potentially
whats a fischer projection
cross, doesnt show middle carbons
most oxidised at the top
how do you assign D/L config?
OH on penultimate carbon on left -> L
on right -> D
haworth projection
the scary thing.
define: anomeric carbon
new stereocentre resulting from cyclic hemiacetal formation. (attached to 2 O’s!)
how are cyclic hemiacetals formed
ketone and OH in carb chain react to form cyclic molecule. makes hemiacetal fg:
RO OH
C
R’ H
define anomer:
carbs differing in config at anomeric carbon. B-anomer (OH cis to CH2OH) and a-anomer
describe mutarotation
change in specific rotation that accompanies the interconversion of a and B anomers in aqueous solution. occurs in EQUILIBRIRUM
-in equilibrium reactions, reaction reverses, aldehyde flips, cyclic hemiacetal made with another amoner
why are chair conformations superior to haworth projections?
while pentoses are planar, hexoses are in chair conformation so it more accurately reps it
how are cyclic acetals formed from cyclic hemiacetals.
OH on hemiacetal and OH on HC chain react to form water and condensation polymer.
significance of cyclic acetals?
can no longer undergo mutaroation
maltose?
2 glucose monomers
a-1,4’-glycoside bond
a-4,1’-glycoside bond
lactose?
galactose and glucose
b-1,4’-glycoside bond
a-4,1’-glycoside bond
