Carbohydrates Flashcards
what sugar molecule is the most abundant
glucose
what is the formula for carbohydrates
Cn(H2O)n
carbohydrates are called ____ _______ aldehydes/ketones
poly hydroxy
what are monosaccharides? can they be broken down? and some examples
simplest sugar units that cant be broken down
ex. glucose, galactose, fructose
sucrose = __________ + __________
maltose = __________ + __________
lactose = __________ + __________
glucose + fructose
glucose + glucose
glucose + galactose
examples of polysaccharides
starch (flour/potatoes) and cellulose (cotton/cell wall)
D = last OH on fischer proj _____
L = last OH on fishcher proj _____
D = right
L = left
what are epimers
sugars that differ config on only 1 C
(OH on right vs. OH on left on one of the C)
on a fischer projection which C are aldehydes/ketones on
aldehydes = C1
ketones = C2
amino sugar vs. deoxy sugar
amino sugar = OH replaced by NH2
deoxy sugar = OH replaced by H
anomeric carbon? for aldoses? for ketoses
carbons that are attached to 2 O atoms
aldoses = C1
ketoses = C2
D sugars (haworth)
L sugars (haworth)
a = OH down
b = OH up
CH2OH = up
a = OH up
b = OH down
CH2OH = down
what are anomers
the same sugar, different anomeric config
what is mutarotation and how does it occur
when sugars change their anomeric config in the presence of solvent/water. Occurs when sugars have hemiacetals (reducing ends)
ex. a —- b or b —- a
can glycosides undergo mutarotation
no they cant bc glycosides are acetals
naming sugar alcohols
D-glucose + NaBH4 =
D-glucitol
what do sugar alcohols have on the end of their structures
have 2 CH2OH, one on each end.
what reagent are sugar alcohols being reduced with
NaBH4
are meso compounds optically active and chiral
No
what do oxidizing agents do
convert aldehyde into COOH
oxidizing agent ex
Tollens Reagent
what does Tollens Reagent do
oxidizes aldehydes into COOH
sugars that react with oxidizing agents are called _______. The reagent is _______ and the sugar is ________.
reducing sugars
reagent = reduced
sugar = oxidized
Tollens test?
- tests for aldehydes and hemiacetals
- unreactive towards acetals (glycosides) and polysaccharides
Can ketoses like fructose react with Tollens Reagent
yes they can, only if they have a ene-diol interconversion. (ketone to aldehyde)
Unknown structure question
if sugar is unreactive towards Tollens Reagent, what does that mean? What type of linkage would this sugar have?
it means its a acetal so a glycoside
(a/b) 1-1 linkage
the acetal end is called the _______ end
non reducing
the hemiacetal end is called _________ reducing end
reducing end
what is the anomeric effect
axial substiuents for EN groups (O,OH,F) in a-anomer, equatorial for EP groups (N)
ex. OH is down for a-anomer = axial
what is the inverse anomeric effect
equatorial substituents for EN groups (O, OH, F) in b-anomer, axial for EP groups (N)
ex. OH is up for b-anomer = equatorial
Solvent Effect?
polar solvent (h2o, dmso) = ________ forces
non polar solvent (CDCL3, THF) = _________ forces
intermolecular forces bc they can bind with solvent for stability.
Solvent - H - Sugar
intramolecular forces bc they cant h bond with solvent, they h bond with sugars for stability
Sugar - H - Sugar
how to name glycosides/glycosidic linkages
(D/L) - sugarsyl - (a/b 1- ) - (D/L) - sugar(pyranose/furanose)
what rxn breaks apart polysaccharides
hydrolysis
what rxn makes di/polysaccharides
condensation/dehydration rxn
what does sugar methylation do
protects the anomeric carbon from other rxns
what does acetalation do to sugar alcohols
converts OH to OAc
pyranose on C1 and C5
furanose on C1 and C4
glycosidases and example
enzymes that cleave specific sugars in glycosides
b-galactosidase = cleaves b-galactose
what does dextran do
seperates polysaccharides into monosaccharides
what linkage is starch made of
poly a(1-4) D-glucose links
what are the 2 forms of starch
amylose (plants) and amylopectin (human foods)
function of starch
energy storage unit and feul
what linkage is amylose made of
poly a(1-4) D-glucose links
function of amylose
energy storage unit in plants
function of glycogen
energy storage unit in humans/animals
what linkage is glycogen made of
poly a(1-4) + a(1-6) D-glucose links, more (1-6 links)
What type of structure does amylose form
tightly coiled helical structure
homopolysaccharide examples
starch, cellulose, chitan, chitosan
heteropolysaccharide examples
peptidoglycans, GAGS, proteoglycans, glycolipids/lipopolysaccharides, glycoproteins
function of cellulose
provides structure and rigidity to plant cell walls
what linkage is cellulose made of
poly b(1-4) D-glucose links
what is the structure of cellulose
formation of long fibers that stack onto each other through h bonding
function of chitan
exoskelatal component of arthopods (insects, crabs, lobsters)
what is the second most abundant polysaccharide
chitan
what is the first most abundant polysaccharide
cellulose
what linkage is chitan made of
poly b(1-4) N-acetylglucosamine NAG links
what linkage is chitosan made of
deacytylated poly b(1-4) D-glucosamine links
how is chitosan made
chitan + NAOH = chitosan
function of peptidoglycans
structural component of bacterial cell wall
what linkage are peptidoglycans made of
poly b(1-4) NAG and NAM
what are GAGs made of
repeating disaccharide units of acetylated amino sugar + uronic acid
where are GAGs found
ECM, specifically connective tissue
what are proteoglycans made of
GAGs + proteins
where are proteoglycans found
ECM, specifically connective tissue
example of proteoglycan
hyaluronic acid
function of proteoglycans
provides hydration and skin elasticity
function of glycoprotiens
aids in cell-cell recognition and cell signalling
structure of glycoproteins
oligosaccharide sugar + proteins
Glycosylation
O-linked =
N-linked =
Serine/Threonine
Asparginine
