Chapter 7 Flashcards
oligosaccharides
3-20 monosaccharides
polysaccharide
polymers more than 20 monosaccharides
glycoconjugates
carbs linked to proteins or lipids
D
OH on right
L
OH on LLLLLLeft
designation of D or L based on…
OH of chiral carbon most distant from carbonyl oxygen called glyceraldehyde
molecules with “n” chiral centers will have ____ stereoisomers
2^n
carbohydrate empirical formula
(CH2O)n
two major classes of carbs
aldoses and ketoses
Glucose and _________ epimers at C-2
Mannose
Glucose and _________ epimers at C-4
Galactose
epimers
sugars that differ at a single chiral center
cyclized structure; alcohol with aldehyde
hemiacetal
cyclized structure; alcohol with ketose
hemiketal
six-membered sugar ring
pyranose
five member sugar ring
furanose
beta
OH above
alpha
OH below
mutarotation
a and B configurations interconverting
sugar derivative glucosinolate and enzyme myrosinase
stored separately, but come together upon tissue damage – myrosinase acts on glucosinolate to produce glucose and isothiocyanate (bitter).
monosaccharides reducing agents
carbonyl group (now reducing end) is oxidized to a carboxyl group to allow for quantifications of sugar in blood or urine
glycosidic bond
primary structural linkage in all polymers of monosaccharides
O-glycosidic bonds
occur through oxygen
N-glycosidic bonds
occur through nitrogen
reducing end
the end of the chain with a free anomeric carbon
glycosyltransferases
how higher order carbohydrate structures are generated
-use monosaccharides activated through linkage with UDP
homopolysaccharides
polymers containing a single type of monosaccharide
heteropolysaccharides
polymers containing more than one type of monosaccharide
energy storage polysaccharides
- starch (amylose and amylopectin)
- glycogen
amylose
unbranched, linear polymer of glucose residues though a(1-4) bonds
non-reducing end suffix
osyl
reducing end suffix
ose
amylopectin
branched, a(1-4) linked glucose residues with a(1-6) branched every 24-30 residues
glycogen
- most prevalent in skeletal muscle and liver
- identical to amylopectin, but branch every 10 residues
glycogen phosphorylase
cleaves glucose residues from branch end points to mobilize
structural polysaccharides
cellulose and chitin
cellulose
-linear, homo of glucose B(1-4)
chitin
principal component of hard exoskeletons
- linear, homo, N-acetylglucosamine (modification of glucose)
- B(1-4)
chemical different between cellulose and chitin
replacement of hydroxyl group at C2 with acylated amino group
fibrils
formed by parallel polysaccharides linked through H-bonds
B(1-4) linkages
- of cellulose and chitin
- allow formation of long straight chains
a(1-4) linkages
-of starts and glycogen form hollow, helical structures, for storage
glycolipids
sugars covalently linked to lipid molecules
glycolipids function
formation of blood group antigens
proteoglycans
protein linked to carb called glycosaminoglycan
-serve structural and lubricating functions
glycoproteins
protein with covalently attached sugars
- (N-linked) amide nitrogen of side chain of an Asn
- (O-linked) hydroxyl on Set of Threonine
erythropoietin (EPO)
glycoprotein that stimulated production of red blood cells
- has 3 n-linked and o-linked glycosylations
- seynthetic differs from endogenous (used to detect use of the banned substance)
extracellular matrix
space in tissues containing gel-like material
