Carbohydrates - Monosaccharides

monosaccharide facts

• sweet tasting

• reducing sugar

• classified by the number of carbons

• ex 3 carbons is a triose, pentose is 5 and hexose is 6.

• contain a carbonyl grp

aldose sugar

when carbonyl group =O is at the end of the chain

ketose sugar

when carbonyl group =O is not at the end of the chain

what do all monosaccharides contain

one or more asymmetric carbon atoms with 4 diff functional groups

basically a chiral carbon

isomers

two compounds having the same molecular formula but a different structural formula

structural isomers

same chemical groups are bound to different carbon atoms

stereoisomers

the same chemical groups are bound to the same carbon but have different 3D orientations

D-sugar

when the hydroxyl group is on the right side - most sugars exist as this form

L sugar

when the hydroxyl group is on the left hand side - amino acids exist in this form

alpha sugars

oh group is below C1

ABBA - alpha below, beta above

Beta sugars

oh group is above c1

abba- alpha below, beta above

glucose structure

Fructose

5 carbon ring and a structural isomer of glucose have a ketone rather then aldehyde

test for reducing sugars

• add blue benedicts solution

• heat

• will turn yellow- brick red