CARBOHYDRATES Flashcards
what are carbohydrates?
basically sugar
what is monosaccharide?
trioses : the simplest monosaccharides
general formula : [CH2O]n
what are glyceraldehyde and dihyroxyacetone?
glyceraldehyde : (=O) at the end of the chain - ALDOSE
dihydroxyacetone : (=O) in the middle of the chain -KETOSE
3 = triose
4 = tetrose
5 = pentose
6 = hexose
what are polysaccharids?
made out of many monomers joined together by glycosidic linkages
galactose + glucose = lactose
glucose + glucose = maltose
what happens when carbohydrates are added to proteins?
from glycoproteins
what is eukaryotic glycosylation?
N-GLYCOSYLATION : Asn-X-Ser Asn-X-Thr O-GLYCOSYLATION : X-Ser-X X-Thr-X
monosaccharides are mostly in what nature?
D-enantiomers except for
can monosaccharides cyclize to form different configurations?
can - hydroxyl group are replaced by amine (NH2) to result is sugar-amines
what are the functions of carbohydrates?
structural roles and energy storage
what is cellulose?
cellulose is very stable and difficult to break apart
- sheets of cellulose stacked and stabilized by hydrogen bonding and van der waals interactions
cellulose in plants?
stability of cellulose provides tremendous strength and allows tress to grow to massive scales, making it difficult to break down cellulose into glucose for biofuels
- wood-eating termites have cellulase ; an enzyme that breaks down cellulose in their gut very slowly
cellulose in invertebrates?
chitin is the major component of invertebrate exoskeletons which provides great strength for protection
what is amylose?
amylase is organised in ribbon shapes and are easily broken because there are fewer bonds within the ribbon.
what is the difference between amylose and cellulose?
they are both made of glucose units but have different structures because of the type of glycosidic bond
- amylose in starch is easily broken down due to alpha-glycosidic bond
- cellulose in plants and invertebrates surfaces is very strong due to beta-glycosidic bond
