Monnosaccharides Flashcards
Sterioisomers:
same atoms in same order, but different spatial arrangements (must have chiral bond)
D=
right
L=
left
Enantiomers:
mirror images
Mutarotations:
when linear monosaccharides take on a cyclic form. (have an additional alpha or beta designation)
Alpha:
hydroxyl group points upward
Beta:
hydroxyl group points downward
Monosaccharides form cyclic structures when one of their alcohol (OH) groups react with an aldehyde (or ketone) group:
Linear monosaccharides are only found when interconverting between various cyclic groups: interconversions=mutations
Oxidation:
can happen at the terminal CH2OH and/or aldehyde end of straight chain forms.
(In blue)
Reduction:
can happen at the aldehyde end of a straight chain
(in red)
Why does glucaronic acid improve water solubility?
It introduces polar groups such as OH (hydroxyl) and COOH (carboxyl) groups into the molecule. These act strongly with hydrophilic molecules drawing more water into the molecule.
Increases glomerular filtration rate (GFR) and reduces absorption in the tubules, which allows for the kidneys to pull it out of the blood easier and expel it through the urine.
Reducing sugar:
a sugar that can reduce a weak oxidizing agent
Reducing sugars are any sugars capable of reopening into the straight chain form.
Cannot have anything other than an OH attached to the anomeric C1 carbon.
What of the following is a reducing sugar?
The structure on the Left, because it has a free aldehyde group.
Testing for sugar in the urine:
Copper containing weak oxidizing reagent called Benedict solution is added to urine, the reducing sugars present will turn reddish brown when it’s reduced.
This is how diabetes mellitus is indicated in urine levels.
Esterifications:
sugar esterification typically involve the formation of phosphate or sulfate esters.
Monosaccharide phosphate esters:
phosphate is a better leaving group than a hydroxyl, so adding a phosphate to a monosaccharide makes it more reactive.
Monosaccharide sulfate esters:
Monosaccharides found in connective tissues are often sulfated.
At physiological pH, these sulfates become negatively charged.
These negative charges attract large amounts of water.
This makes CT less dense, so it can occupy 1000’s of time as much space than if packed tightly together.
Glycoside formation:
Glycosides are sugars in which the OH group on the anomeric carbon is replaced by an alcohol, forming a glycosidic link.
Glycosides as heart medications:
Digoxin: extract from digitalis lanata
“cardiac” glycoside: can improve the contraction of the heart
(useful for someone with congestive heart failure)
Monosaccharide derivitives:
What is the importance of deoxyribose?
crucial component of DNA. Carries all the genetic information of all living organisms.
Disaccharides:
glycosides formed when two sugars join via a glycosidic link.
Naming a disaccharide:
Alpha and beta designations come from the OH positions at C1 of the 1st and 2nd monosaccharide.
The numeric designations come from the carbons associated with the glycosidic bond.