Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
44 Cards in this Set
- Front
- Back
carbohydrates organization |
organized by their number of carbon atoms and functional groups |
|
common names for sugars |
glucose fructose galactose |
|
three-carbon sugars |
trioses |
|
four-carbon sugars |
tetroses |
|
aldoses |
sugars with aldehydes (the CHO) as their most oxidized group |
|
ketoses |
sugars with ketones (ROR) as their most oxidized group; can act as reducing sugars because they undergo tautomerization to undergo keto-enol shifts which forms an aldose |
|
nomenclature of all sugars is based on |
the D- and L- forms of glyceraldehyde |
|
D-sugars |
sugars with the highest-numbered chiral carbon with the -OH group on the right (in a Fischer projection) |
|
L-sugars |
sugars with the highest-numbered chiral carbon with the -OH group on the left (in a Fischer projection) |
|
D- and L- forms of the same sugar are |
enantiomers |
|
enantiomers |
chiral molecules that are mirror images of each other; non-superimposable; have equal but opposite optical activities |
|
diastereomers |
nonsuperimposible configurations of molecules with similar connectivity; they differ at at least one, but not all, chiral carbons; these include epimers and anomers |
|
epimers |
subtype of diastereomers that differ at exactly one chiral carbon |
|
anomers |
subtype of epimers that differ at the anomeric carbon; this is in cyclic compounds |
|
cyclization |
describes the ring formation of carbohydrates from their straight-chain forms; when rings form, the anomeric carbon can take on either an α- or β-conformation |
|
anomeric carbon |
the new chiral center formed in ring closure; it was the carbon containing the carbonyl in the straight-chain form |
|
α-anomers |
have the -OH on the anomeric carbon trans (pointing down) to the free -CH2OH group |
|
β-anomers |
have the -OH on the anomeric carbon cis (pointing up) to the free -CH2OH group |
|
Haworth projections |
provide a good way to represent three-dimensional structure (in cyclic compounds) |
|
mutarotation |
cyclic compounds can undergo this process in which they shift from one anomeric form to another with the straight-chain form as an intermediate |
|
monosaccharides |
single carbohydrate units, with glucose as the most commonly observed monomer; they can undergo three main reactions: oxidation-reduction esterification glycoside formation |
|
aldonic acids |
form after the aldehyde group on a reducing sugar reduces another compound, becoming oxidized in the process; an aldose which has been oxidized |
|
alditols |
aldoses that have been reduced |
|
reducing sugars |
sugars that can be oxidized and are reducing agents |
|
reagents used to detect reducing sugars |
Tollen's or Benedict's reagents |
|
deoxy sugars |
sugars with an -H replacing an -OH group |
|
esterification |
the process of sugars reacting with carboxylic acids and their derivatives and forming esters |
|
phosphorylation |
reaction in which a phosphate ester is formed by transferring a phosphate group from ATP onto a sugar |
|
glycoside formation |
refers to the reaction between an alcohol and a hemiacetal or hemiketal group on a sugar to yield an alkoxy group (alkyl group singularly bonded to O); the basis for building complex carbohydrates and requires the anomeric carbon to link to another sugar |
|
disaccharides form as result of |
glycosidic bonding between two monosaccharide subunits |
|
polysaccharides form by |
repeated monosaccharide or polysaccharide glycosidic bonding |
|
common disaccharides include |
sucrose (glucose-α-1,2-fructose) lactose (galactose-β-1,4-glucose) maltose (glucose-α-1,4-glucose) |
|
cellulose |
a polysaccharide which is the main structural component for plant cell walls and is a main source of fiber in the human diet; linked by β-1,4 glycosidic bonds |
|
starches (amylose and amylopectin) |
polysaccharides which function as a main energy storage form for plants |
|
glycogen |
a polysaccharide which functions as a main energy storage form for animals; linked by α-1,4 glycosidic and α-1,6 glycosidic bonds; very highly branched |
|
glucose |
an aldohexose (meaning it has one aldehyde group and six carbons); has 4 chiral carbons (16 stereoisomers) |
|
tautomerization |
a rearrangement of bonds |
|
β-amylase |
cleaves amylose at the nonreducing end of the polymer to yield maltose exclusively |
|
α-amylase |
cleaves amylose anywhere along the chain to yield short polysaccharides, maltose and glucose |
|
debranching enzyme |
removes oligosaccharides from a branch in glycogen or starches |
|
glycogen phosphorylase |
yields glucose 1-phosphate |
|
amylopectin |
type of starch linked via α-1,4 glycosidic bonds and α-1,6 glycosidic bonds; highly branched |
|
amylose |
type of starch linked via α-1,4 glycosidic bonds |
|
hemiacetals and hemiketals |
cyclic forms of monosaccharides |