Chapter 4: Carbohydrate Structure and Function Flashcards
aldoses
aldehyde group as their most oxidized fucntional group
ketoses
ketone group as their most oxidized fucntional group
glyseraldehyde
basic structure of an monosaccharide
dihydroxyacetone
simplest ketose
enantiomers
nonidentical, nonsuperimposable mirror image of each other. it is different in every chiral carbon. they must be opposite absolute configurations
number of stereoisomers with common backbone=
2^n
n is the number of chiral carbons
horizoantal lines are wedges and are _____
out of page
vertical lines are dashes and are ____
into the page
D- sugars have their hydroxide group of thier highest chiral center on their ___
right
L- sugars have their hydroxide group of thier highest chiral center on their ___
left
3 types of stereoisomers:
1) enantiomers: the same sugar in different optical families (such as D-gluose and L-glucose)
2) diastereoisomers: 2 sugars that are in the same family, but are not identical and are not mirroe images of each other
3)epimers: diastereomer that differes in only once chiral center
hemiacetal
from aldoses
hemiketal
from ketoses
pyranoses
six-membered rings
furanose
five-membered rings
anomers
two molecules that differ in their anomeric crbon, they can be alpha and beta.
haworth projection
any group in the right of a fisher projection goes down in the haworth projection
beta-anomer
has the -OH group on the C-1 cis to the CH2OH substituint (equatorial and up)
alpha-anomer
has the -OH group on the C-1 trans to the CH2OH substituint (axial and down)
mutarotation
exposing hemiacetal rings to water will cause them to open and close
interconversion between alpha and beta anomers via ring open and close
the alpha anomer configuration is less favorabke because the hydroxyl group of the anomeric carbon is axial, adding to the steric hinderance of the molecule
aldonic acids
oxidized aldoses, they are carboxylic acids
reducing sugar
any monosaccharide with a hemiacetal ring
lactone
cyclic ester with a carbinyl group persisting on the anomeric carbon. Contains a cyclic ester.
tollen’s reagent
produce a silvery mirror when aldehyde are present
tautomerization
ketones can be tautomerized to form a aldose under basic conditions via keto-enol shifts. it does the rearrangement of bonds in a compound, usually by moving a hydrogen and forming a double bond.
benedict’s reagent
red precipitate of Cu2O
enol
compond with a double bond and a alcohol group
esterification
carboxylic acid derivatives to form esters
phosphate ester
esterification is very similar to the phosphorylation of glucos in which phosphat ester is formed
hemiacetals react with alcohol to form ___
acetals
glycoside formation
the anomeric hydroxyl group is tranformed into a alkoxy group, yielding a mixture of alpha and beta acetals (with water as a leaving group). The resulting is a carbon-oxygen (C-O) bonds are called glycosidic bonds, and the acetals formed are glycosides.
sucrose
glucose-alpha-1,2 - fructose
disaccharides
glycosidic bonds formed between hydroxyl groups of two monosaccharides result in the formation of a disaccharide. Most common are sucrose, lactose and maltose
lactose
galactose-beta-1,4-glucose
maltose
glucose-alpha-1,4-glucose
polysaccharides
long chains of monosacchairides linked togetehr by glycosidic bonds
heteropolysaccharides
different ypes of monosaccharides
homopolysaccharides
same type of monosaccharides
starches
They are linked alpha-d-glucose monomers.
Plants store starch as amylose, a linear glucose polymer via alpha-1,4 glycosidic bonds. Another types is amylopectin, which has alpha-1,4 glycosidic bonds and branches with alpha-1,6 glycosidic bonds.
betha-amylase: cleaves anylose at the nonreducing end of the polymer. Yield maltose.
alpha-amylase: cleaves randomly along the chain to yield shorter chains
cellulose
beta-d-glucose molecules linked by beta-1,4 glycosidic bonds, with hydrogen bonds holding the polysaccharides together
glycogen
storage unit in animals
it has more alpha-1,6 glycosidic bonds, it is th emost branched compound It makes it more soluable in solution, thereby allowing more glucose to be stored in the body. Glycogen phosphorylase is an enzyme that functions by cleaving glucose from the ninreducinf end of a glycogen branch and phosphorylating it, thereby producing glucose 1-phosphate, which plays a important role in metabolism.
