Lecture 2 Carbohydrates: Disaccharides and Polysaccharides Flashcards
What is the bond that links monosaccharides?
glycosidic bond
How are glycosidic bonds formed?
Formed by the reaction of the carbon derived from a carbonyl group (anomeric carbon) of one sugar molecule with a OH group of another (sugar) molecule to form O-glycosidic bonds.
When is an anomeric carbon non-reducing/ reducing?
- reducing: the O of the anomeric carbon is available to react (not attached to some other structure such as metal or other sugar)
- non-reducing: the O of the anomeric carbon is attached to another structure
anomeric carbon
In a cyclic carbohydrate, the carbon that was the carbonyl carbon in acyclic form.
Reducing sugar
any sugar that is capable of acting as a reducing agent.
- In an alkaline solution, a reducing sugar forms some aldehyde or ketone, which allows it to act as a reducing agent.
How does the acetal form in lactose?
Functional group formed by the nucleophilic addition of an alcohol to aldehyde or a ketone.
Difference between hemiacetal and acetal
The critical difference between hemiacetal and acetal is that hemiacetal contains one -OH and one -OR group while acetal contains two -OR groups.
What cleaves lactose and sucrose
lactase and sucrase
What are the three most important polysaccharides?
- starch
- glycogen
- celluose
What are the two types of starch?
amylose and amylopectin
What are starch, gylcogen and cellulose all made up of?
glucose based homo polysaccharides
What is the most abundant polymer in the world?
Cellulose
- major polysaccharide of trees and grass
Structure of cellulose
linear polymer of ß(1→4)-linked glucose units.
What can digest cellulose?
The microbial or fungal enzyme, cellulase but aside from ruminants, most animals do not produce cellulase so can only partially break it down through fermentation, limiting energy availability from cellulose
Where does most heat come from when wood burned
oxidation of cellulose
