carbohydrate structure Flashcards
constitutional isomers
order of atoms change
constitutional isomers are
tautomers
fisher projections are
linear versions of carbohydrates
stereoisomers
have the same connectivity but different spatial organizations
types of stereoisomers
configurational isomers and conformational isomers
configurational isomers
have chiral carbons
types of configurational isomers
diastereomers and enantiomers
enantiomers
are mirror images at all chiral centers
diastereomers
have multiple chiral centers; not all chiral carbons are mirror images
D/L nomenclature is determined by
direction of last chiral carbon’s -OH group
haworth projections
are the cyclical versions of carbohydrates
steps to convert from fisher to haworth projections
- choose ring
- the carbonyl carbon goes 1 position clockwise from the oxygen
- number carbons clockwise
- the =O becomes OH, and UP is beta while DOWN is alpha
types of diastereomers
epimers and anomers
anomers differ at
the anomeric carbon only (i.e. alpha vs. beta)
epimers differ
at any other carbon than the anomeric carbon (i.e. same alpha or beta but different somewhere else)
conformational isomers
have reversible rotation changes
e.g. nucleotides
glycosides
are formed when one or more hydroxyls are replaced
fucose
- galactose derivative - methyl added onto C-
- only L-monosaccharide made and used by animals
- part of A/B/O blood antigens
excess free fucose in blood
liver damage
cancer
diabetes
heart disease
modified monosacchrides - phosphorylation
phosphates have _____ linkages
ester
- sugar phosphate backbone in nucleic acids
- important reactive intermediates in carbohydrate metabolism
- adds negative charge
- phosphate from ATP
- name tells where to put the phosphate
modified monosaccharides - oxidation
- reducing sugars are:
- 2 step process, makes:
- an antiquated:
- oxidized at the carbonyl (anomeric carbon)
- acids and lactones
- diabetes urine test
reducing sugars are
monosaccharides
modified monosacchardies - reduction
- reduction at the carbonyl makes:
- ______ can cause cataracts it if accumaultes in the lens of the eye
- alditols
- sorbitol
modified monosaccharides - amino sugars
- found in branched:
- common additions to:
- ___ - linked glycosides
- polysaccharides (e.g. cell walls)
- proteins
- N-linked
modified monosaccharides - methylation
- ____ - linked
- same reaction that creates _________ , but with a non-sugar
- O-linked
- polysaccharides
some important toxins are
O-linked glycosides
essential monosaccharides
Regular monosaccharides:
- D-Glucose
- D-Galactose
- D-Mannose
- D-Xylose
the oddball:
- L-Fucose
Amino sugars:
- GlcNAc
- GalNAc
- Sialic Acid
Maltose:
anomeric carbons:
disaccharide consisting of 2 glucoses
1 and 4
lactose
anomeric carbons:
disaccharide consisting of 1 galactose and 1 glucose
1 galactose and 4 glucose
sucrose
anomeric carbons
disaccharide consisting of 1 glucose and 1 fructose
1 glucose and 2 fructose
roles for polysaccharides
- glucose storage (alpha linkages)
- structure (beta-linkages) e.g cellulose
- protein diversity (N-linkages through Asn) (O-linkages through Ser or Thr)
is amylose branched or unbranched
unbranched
one structural polysaccharides essentially is universal:
chitin
glycoproteins:
- protein ____ sugar (by weight)
- on membranes, involved in:
- on soluble protesin, involved in:
- >
- cell adhesion
- cell signaling
glycosaminoglycans:
- sugar ____ protein (by weight)
- repeating ____ units
- sugar component of proteoglycans are involved in:
- >
- dissacharide
- cartilage, blood clotting, chitin
mucins:
- sugar ____ protein (by weight)
- more complex patterns than ____ repeats
- lubrication = ____ + ____
- >
- disaccharide
- protection + hydration
glycolipids decorate cell ____ and are used to recognize ____
membranes
self/others
(ABO blood typing)
difference between O-B blood types
addition of a galactose
difference between O-A blood types
acetyl-galactose amine group
difference between A-B blood types
difference is only an N-linked acetyl
