Carbohydrates Flashcards
What are the 3 structure tiers of carbohydrates?
Monosaccharides, disaccharides and polysaccharides
How many units are there in a monosaccharide?
single (one)
what are the 2 classes of monosaccharide?
aldoses or ketoses
How many carbons are there in monosaccharides?
3-7
Name 5 common monosaccharides
ribose, glucose, mannose, galactose and fructose
How many monosaccharides are there in a disaccaride?
2
What are the monosaccharides joined by to produce disaccharides?
glycosidic bond
Name 3 common disaccharides
lactose, maltose and sucrose
What are polysaccharides?
polymers of 20 or more monosaccharides
Name 3 common polysaccharides
cellulose, starch and glycogen
What makes up an aldehyde group?
carbon bonded to hydrogen and double bonded to oxygen
What is the name of the monosaccharides that have an aldehyde group?
aldoses
What makes up a ketone group?
carbon double bonded to oxygen
What is the name of the monosaccharides that have a ketone group?
ketoses
What further way can monosaccharides be classified?
by the number of carbon atoms they contain
How many carbon atoms are there in a triose, pentose and hexose sugar?
3, 5 and 6
What are stereoisomers?
molecules made of the same atoms, connected in the same sequence but the atoms are positioned differently in space
Why do almost all monosaccharides exist as 2 stereoisomers?
all contain one or more asymmetric (chiral) carbon atom
What are enantiomers?
two stereoisomers that are mirror images of each other
What is an example of a molecule that exists as two enantiomers?
glyceraldehyde - two stereoisomers that are mirror images of each other
What are the two forms of sugar stereoisomers?
D- or L-
What type of sugar stereoisomers are most common in animals?
D- isomers
What are epimers?
sugars which differ in the configuration around one carbon atom
What structure do the common monosaccarides have?
cyclical