Carbohydrate Chemistry Flashcards
What are carbohydrates involved in?
Involved in cell communication
Tumour metastasis
What is a carbohydrate?
Generic term for C=O containing organic molecules with hydroxyl OH groups
Carbohydrates are polymers of small sugars
What is the generic formula?
Cn(H2O)n
How do you name a carbohydrate?
1) position of C=O
2) number of carbons
3) stereochemistry
What is D and L?
They describe stereochemistry
They are enantiomers of each other (mirror image)
How do you determine D or L
Is the OH of the highest stereochemical centre facing the same way as D- glyceraldehyde? (Facing right)
Yes= D (right)
No= L (left)
What is an epimer?
It is a diastereoisomers
What is a monosaccharide?
A simple single sugar unit
What is a disaccharide?
2 monosaccharides linked together
What is a oligoaaccharide?
3-10 monosaccharides linked in a chain
What is a polysaccharide?
Long chains of sugars
How is a hemiacetal formed
Aldehyde reacting with an alcohol
Makes a chiral hemiacetal
How do you form a pyranose?
A pyranose is a 6 membered ring
Formation of cyclic ring form is simply hemiacetal formation (intermolecular)
The OH reacts with carboxylic acid to make a cyclic acetal
What is the c1 position
Anomeric carbon - this is carbon closest to where hemiacetal was formed, next to O
How can you tell is a pyranose is beta or alpha?
If it has an axial OH at C1 it is alpha
If it has an equatorial OH at C1 it is beta
Describe the configuration of pyranose glucose
All equatorial OH groups and all axial H groups
What is a faranose?
5membered ring
How can you represent sugars?
Fischer projection- linear and horizontal
Haworth projection- ring 2D
Chair- flying wedge with axial and equatorial
What is a glycosidic bonds?
-O-
What is mutarotation?
Hemiacetal formation is reversible- you can reopen the ring
Interconversion is called mutatotation
(See mechanism)
How can sugars form glycosides?
Hemiacetal + alcohol goes to acetal and water
What is the disaccharide of glucose?
Maltose
What important disaccharides are there?
Maltose, Lactose (Made from glucose and galactose) Sucrose (Made from glucose and fructose)
What is starch?
Polysaccharide in plants- long polymer chain of glucose
Food storage in plants (glycogen in animals)
What is cellulose?
This is a structural polysaccharide of glucose
Can form H bonds which are very strong
What is the bacterial cell wall made up of?
It is made up of peptidoglycan (overall)
Long polymer of sugars linked to peptides
Made up of glcNAC and Nacetyl nuanic acid
