carb test Flashcards
how do ketoes based rings form?
the C5 attacks C2. this is for fructose furanose
how do aldose based rings form?
C5 attacks C1 to form a pyranose and C2 to form a ketose
what is the most sable sting structure and why?
when in the chair conformation. this is because in this conformation the substituents in the axial plan have the least amount of steric hindrance
is ring closure an intra or inter-molecular process?
intramolecletuar. this open form attacks itself
what is a hemi ketol? hemi acetol?
the group of molecules that attach to a C to form the anomeric centre
(c)OH,OR,R,R’
what are the monom saccharides that we need to know
fructose = hexose and ketol
ribose = pentose
glucose, mannose, galactose
what is sucrose made of
glucose and fructose
what is maltose made of
2 glucose
what is galactose made of
galactose and glucose
what is a glycosidic bond
the bond between an anomeric carbon and an alcohol from another molecule
what is a reducing sugar
the ability for a monosac to interconvert between the ring and closed ring form as the anomeric carbon is not involved in glycosidic bonds. The aldehyde group interacts with an oxidizing agent to donate protons and break the bond
note that the mon sac does not need to be an adlose for this to occur, due to tautomerization, a mono sac can go back and forth between ketone and an aldose.
how can glucose be stored in the body?
either as glycogen or starch (amylose or amylopectin)
what enzyme breaks down glycogen and starches
alpha-amylase
what is inulin
as energy storage in plant comprised of glucose attaches by B2,1 glycosidic bonds
O linked glycosylation
carbs that are attached to a protein via forming a glycosidic bond with the hydroxyl group of a side chain residue
anomeric carbon attaches to Serine or threonine
why does glycosylation change the properties of a protein
once attached to another mole, the og carb gains chemical information (diversifies them) and is more likey to be able to participate is a wider variety of functions
glycosylated protein vs lectin
N linked glycosylastion
carbs that attach to a protein via forming a glycosidic bond with the amino group of a side chain residue. All N linked oligo sacs have a 5 sugar core (3 mannose, 1 six C sugar (commonly mannose) and 2 N-acetylglucoamines)
anomeric carbon attached to terminal Asparginine
which enzyme catalyses the linkage of proteins with carbs?
glycosyltransferase. activated sugars (bound to UDP) are bound to the AA residue unit)
on which glyco protein are more sugars are able to attach to?
N linked. this is because of the 5 sugar core.
what factors dictate the richness of chemistry found in carbs?
1) the number of gly bonds
2)the total number of mono sacs joined together
3)the proportions of anomeric conformations (a vs B)
4)how they attach to proteins
what are the three classes of glyco proteins
1) glycoproteins
2) proteoglycans
3) mucins
what are glycoproteins
a carb and prot unit of which proteins constitute the majority of the mass of the mole
what are proteoglycans
a carb and prot unit of which carbs make up the majority of the mass
the carb that dominates here is a glycosaminoglycan
these models function structurally in tissues and as a lubricant. overall these moles have a negative charge which is able to induce the movement of water into or out of tissues based on pressure (like in the heal)
what are mucins
a carb and prot unit of which carbs make up the majority of the mass
the carb that dominates is a N-acetylgalactosamine.
these models function as a lubricant and have a defining VTR backbone. along the backbone ser and Thr attach to the carbs moles. commonly they will bond to epithelial cells to form a gel and protective barriers
what are lectins
proteins that specifically bind to carbs via non covalent interactions. commonly, they will bind glycoproteins to other surfaces.
selectins bind immune system cells to injury sites
