Lecture 8: Carbohydrate Flashcards
Carbohydrates (2)
What it is+used for
- Carbon-based molecules with many hydroxyl groups
- Used for energy storage, cellular recognition
Simple carbohydrate
Monosaccharides
Complex Carbohydrates
polysaccharides: polymers of covalently linked monosaccharides
Storage form of carbs
Glycogen
Carbs and its structural role
exoskeleton of insect (chitin), cell wall of plants, fungi and bacteria
carbohydrate formula+where they differ by
(CH2O)n
- where carbohydrates differ by the n and stereochemistry
Fisher projection (3)
- Open chain form of carbohydrate
- Horizontal bonds outwards
- Vertical bonds project backwards
Aldehyde
Keytone
Ketose
- 1 ketone group with two or more hydroxyl groups
Aldose
- 1 aldehyde group with two or more hydroxyl groups
D and L (4)
seen in+ the two+biological
- present in aldose
- D is OH group on right hand side
- L is OH group on left hand side
- Biological form is D
D or L is determined by
- the asymmetric carbon farthest from the aldehyde or ketone
- if the –OH group attached to the bottom-most asymmetric center (the carbon that is second from the bottom) is on the right, then, the compound is a D- sugar. If the –OH group is on the left, then, the compound is a L-sugar.
Constitutional isomers
Differ in the order of attachment of atoms
Stereoisomers
- The the same order of attachment of atoms but diff in spatial arrangement
Enantiomers
Non-super imposible mirror image
Example: D-sugars & L-sugars
Disatereomers (4)
What they are+ formula+different+ ex
- Isomer that are not mirror images
- same formula and connectivity
- Diastereomers have different physical properties (e.g., water solubility)
- epimers and anomers
Epimer (2)
type of +what is it
- type of diastereomer
- carbohydrates that differ in the location of the chiral centre of a -OH group in one location.
Anomers
Differ at a new asymmetric carbon atom formed on ring closure.
Ring closure: Why does it happen? (2)
- Aldehyde and alcohol group react with eachother
- Ketone and alcohol groups can react with eachother
Pyran
six membered ring
Furan
five membered ring
Anomeric Carbon
A carbon derived from the carbonyl carbon (the ketone or aldehyde functional group) of the open-chain form of the carbohydrate molecule.
alpha form in ring closure
OH attached to the anomeric carbo points down (Trans)