Lecture 19: carbohydrate structure Flashcards
What are the 3 types of isomers?
- Constitutional
- Configurational
- Conformational
Describe constitutional isomers
The order of the atoms changes but the molecule formula stays the same. They are tautomers…
Describe stereoisomers
The atoms are connected in the same way but differ in spatial arrangements
Describe configurational isomers
have chiral carbons; can be divided into diastereomers and enantiomers
Define enantiomers
non-superimposable mirror images at ALL chiral centers (D vs L)
Define diasteeomers
isomers that are NOT mirror images, usually has more than one chiral carbon; can be divided into epimers and anomers
Describe the differences between a Fischer projection and the Hawthorne projections
Fischer projection are the linear versions of carbohydrates and the Hawthorne projections are cyclical versions of the carbohydrates
What are the different types or sugar derivatives?
- Fuctose
- Esters (phosphorylation)
- Oxidation/reduction (alcohols)
- N-linkages (amino sugar, nucleotides
- O-linkages (methylation, toxins)
Describe the structure of maltose
alpha-D-glucopyranosyl (1-4) and alpha-D-glucopyranose
Describe the structure of sucrose
alpha-D-glucopyranosyl (1-2) and Beta-D-fructofuranoside
Describe the structure of lactose
Beta-D-galactopyranosyl (1-4) and Beta-D-glucopyranose
Describe glycogen
alpha 1,4 glucose with an alpha 1,6 glycosidic linkages
Describe cellulose
Beta (1,4) linkages of glucose
Describe proteoglycans `
protein+glycosaminoglycans with the carbohydrate making the bigger portion pf the molecule. has repeating disaccharide units
Describe glycoproteins
carbs+proteins where the protein is the biggest portion of the weight of the molecule
Define conformational isomers
reversible rotation changes
Describe fuctose
It is derived from galactose
Only L monosaccharide made and produced by animals
ABO Blood antigens
Excess free fuctose floating around in the blood causes bad shit to happen- liver damage, cancer, diabetes
Describe phosphorylation in monosaccharide modification
phosphates are important reactive intermediates in carbohydrate metabolism, usually derived from ATP
-adds a negative charge to the molecule
(Name tells you where to put the phosphate)
Describe oxidation in regards to monosaccharide modifications
oxidized at the carbonyl (the bond between the O in the ring and the C to the right) and can either make acids or lactones
Describe reduction in regards to monosaccharide modification
reduction at the carbonyl makes alditols (the carbonyl that is at the top of the molecule (COOH) turns into an alcohol
What is a common example of monosaccharide reduction in the body?
The reduction of D-glucose to D-glucitol, also called sorbitol, which can cause cataracts in the eye if it accumulates in the lens of the eye
Describe amino sugars in regards to modified monosaccharides
found in branched polysaccharides (cell walls) and are commonly added to proteins
occur in N-linked glycosides
- amine: NH2
- acetyl: carbonyl attached to a methyl group
- lactic acid CH(CH3)COO-
What are the essential monosaccharides?
D-Glucose D-galactose D-mannose D-xylose L-fuctose GlnNAc GalNAc Sialic Acid
What are the roles of polysaccharides?
- Glucose storage (glycogen, amylose, cellulose)
- Structure (chitin is universal)
- Protein Diversity (glycoproteins, glycosaminoglycans, mucins)
Describe chitin
Is a polysaccharide that is ESSENTIAL for structure
Beta-1,4-linkages of glucose
Describe mucins
Sugar outweighs the proteins
provides lubrication which protects and hydrates
Describe glycolipids
decorate cell membranes, and are used to recognize self and each other
