Biological Molecules And Analytical Molecules Flashcards
Describe the structure of a carb
Carbon and water
Cn(H20)n where n >3
Contain chiral carbons
What are monosaccharides
Can’t be converted into smaller sugars by hydrolysis
What are polysaccharides
Complex carbs made of many sugar monomers linked together
Difference between D and L sugar
D - find the highest number chiral carbon, if OH on the right in a fisher projection , more common in the human body
L - highest number chiral carbon OH on the left
*not the same as R/S configuration
Mcat tip for determining the stereochemical relationship for monosaccharides
Epimer- differs at one chiral carbon
Enantiomer - differs at all chiral carbons
Diastereomer - differs at 2 or more or more chiral carbon
Because carbs have a carbonyl and hydroxyl group on the same molecule what can they form
Cyclic hemiacetal or cyclic hemiketal
D-glucose — pyranose
D-fructose — furanose or pyranose(more stable)
What is an anomeric carbon
When pyranose or furanose form a new chiral centre is generated at the carbonyl carbon
This is the carbon that has 2 oxygen groups attached to it
What is the difference between the alpha and beta anomer
Anomeric OH group C1 is trans to the CH2OH at C5 in the alpha and is cis for the beta
Beta is preferred
A monosaccharide with an alcohol forms a cyclic acetal or ketal, which form is favoured alpha or beta
Alpha (trans)
What is a glycoside
Cyclic carb in which the OH on the anomeric carbon is replaced with an OR
Glycosidic bond is formed where the OH on the anomeric carbon is
What are reducing sugars
All hemiacetal monosaccharides
Some ketones - resulting from isomerazation mechanism fo which must include the enol keto tautomerzation
Any disaccharide with a free OH at the anomeric carbon
What are non reducing sugars
All acetals or ketals (glycosides)
Lactose consists of
D galactose and D glucose
Beta 1,4
Maltose consists of
Two D-glucose
Alpha 1,4
Sucrose consists of
D glucose and D fructose
1,2 glycosidic bond between both anomeric carbons
