Lecture 14 Carb Structure Flashcards
What is a constitutional isomer?
Two molecules with same atoms but different connectivity, they are tautomers
What are these
Ribose on left an aldose sugar
Ribulose on right a ketose sugar
They are tautomers
What are stereoisomers?
Have the same connectivity but different spatial orientations. Branched into configurational or conformational isomers
What are configurational isomers?
They have chiral carbons and branch into enantiomers or diasteromers
What are enantiomers?
Mirror images at all chiral centers
What form are most sugars in?
D
What are diasteromers?
They have multiple chiral centers and not all chiral carbons are mirror images.
What is an Anomer?
Type of diasteromer that differs only at the anomeric C. (the carbon that is next to the O in a Haworth projection) For example alpha vs beta positioning. Beta is up and Alpha is down
What are epimers?
Branch of diasteromer that differs at any other carbon except the anomeric. Same alpha or beta but something else is different.
When converting from Fisher to Haworth what side goes beta and alpha?
The left side of the fisher projection will go up so beta and the right side will be down so alpha position.
What are conformational isomers?
They have reversible rotation changes
D-glyceraldehyde, an aldose sugar
a constitutional isomer of D-Dihydroxyacetone
What type of isomer are these and what are they?
Constitutional isomer (tautomers)
top is D glyceraldehyde and bottom is D-dihydroxyacetone a ketose sugar
What is this?
D ribose, a pentose aldose sugar
Tautomer to D-Ribulose
What is this?
D-Deoxyribose, an aldose pentose sugar
differs from ribose at carbon two H instead of OH
What is this?
Glucose
What is this?
Galactose, an aldose hexose sugar
What is this?
Mannose an aldose hexose sugar
What is this?
Ribulose, a ketose pentose sugar
What is this and what are its tautomers?
Fructose, a ketose hexose sugar. Tautomer of Glucose and mannose
What are glycosides?
Formed when one or more hydroxyls are repleaced by fucose, estrs, redox, N linkages, or O linkages
Describe Fucose.
- Only L momosaccharide that is made by mammals
- Derivitive of galactose
- Part of A/B/O blood ag’s
why is phosphorylation of monosaccharides important?
- part of nucleic acids
- reactive intermediates in carb metabolism
- adds negative charge
- uses ester linkage and name says where its at
where are reducing sugars oxidized and what results?
oxidized at carbonyl and makes acids(middle) and lactones(right)
what does reduction at carbonyl create?
- alditols
- also if glucose is reduced to sorbitol it can cause cataracts
What are the essential monosaccharides?
- Glucose
- Galactose
- Mannose
- Xylose
- L-Fucose
- GlcNac
- GalNAc
- Sialic Acid
What kind of connection is seen, what carbons are connected, where are the anomeric carbons, are the monosaccharides the same or different?
- alpha connection (1,4-alpha-D-glucopyranose, aka maltose)
- Carbons 1 and 4 are connected
- Anomeric carbons are next to the O clockwise
- They are both glucose
What connection is seen, what carbons are connected, where are the anomeric carbons, what are the monomers?
- Alpha connection (1,2-Beta-D-fructofuranoside, aka Sucrose)
- Carbons 1 and 2 are connected
- Anomeric carbons are next to the O five membered ring goes counter clockwise
- Glucose and Fructose
What connection is seen, what carbons are connected, where are the anomeric carbons, what are the monomers?
- Beta connection (1,4-Beta-D-glucopyranose, aka lactose)
- Carbons 1 and 4
- next to O clockwise
- Galactose and Glucose
What is the role of polysaccharides?
- Glucose Storage
- Structure, tends to be Beta linkages, Ex: Chitin
- Protein diversity
What AA can an N linkage occur on?
Asn only
What AA can an O linkage occur on? Significance of this?
Ser or Thr
Allows protein diversity
Describe glycoproteins.
- More protein than sugar by weight
- When they are found on the membrane they are for cell adhesion
- When found on Soluble proteins they are for cell signaling
Describe Glycoaminoglycans.
- More sugar than protin by weight
- Repeating dissacharide units
- Sugar component of proteoglycans
Describe Mucins..
More sugar than protein by weight
More complex pattern than just disaccharide repeats
For lubrication protection and hydration
