carbohydrates Flashcards
what makes sucrose
glucose and fructure
what makes lactose
galactose and glucose
what determines whether a monosacc is an aldose or ketose
the carbonyl carbon.
what is an enantiomer
both molecules are mirror images of each other depending on where the OH group is. if it is on the left = L config
it is on right = D config
what is a diasteromers
when two sugars have identical molecular formula, a diff arrangement of atoms and are not enantimers
what governs whether an amino acid is L or D config
the NH3 group
what is an epimer
a subgroup of diastereoisomers where there is only one difference at one chiral centre- are NOT mirror images so they are not enantiomers.
are ring or linear structures more stable
ring- they typically predominate since they are lower in energy
what happens to the carbonyl carbon after completion of cyclic structure
reduced to an alcohol
which sugars typically undergo intramolecular cyclization
pentoses and hexoses
what happens to the carbonyl carbon after cyclization
it becomes a new chiral centre called the anomeric carbon- at C1 of aldoses and C2 of ketose
what is a pyranose
six membered oxygenated ring with a pyran structure
what is a furanose
five membered oxygenated ring with the furan structure
can glucose adopt a furanose strucrure
yes as well as its pyranose form
does pyranose or furanose forms dominate glucose at equilibrium
pyranose
how do disaccharides form ? (maltose)
where an OH of one glucose condenses with the intramolecular hemiacetal of the other glucose , where H2O is eliminated and a glycosidic bond is formed
what is an O-glycosidic bond (reducing)
where a disaccharide is formed by linkage between two anomeric carbons. the product of this linkage is one acetal group and one hemiacetal.
there is a reducing end
what is an O glycosidic bond (non reducing)
where linkage occurs between two anomeric carbons. the end product has two acetal groups and no hemiacetals. there are no reducing ends
how can you tell if a sugar is a reducing sugar
if the O2 on the anomeric carbon is not attached to any other structure, it is a reducing sugar.
what are the two types of polysaccharides
homo-poly saccharides = one monomer unit
hetero-polysaccharides = multiple monomer units
linear= one type of glycosidic bond
branched= multiple types of glycosidic bonds
what types of bonding does cellulose have
B glucose 1-4
what type of bonding does amylose and amylopectin have
amylose = a 1-4
amylopectin = a 1-4 or 1-6
what type of bonding does glycogen have
a 1-4 and a 1-6
what type of polysaccharide is glycogen
branched homopolysaccharide
