Flashcards in Chapter 7 Carbohydrates Deck (17)
# 1 Why are monosaccharides appropriately named carbohydrates?
# 2) Why are monosaccharides soluble in water but not in non-polar solvents?
Soluble in water, because of the presence of multiple hydroxyl groups.
#3) What are the naming conventions for monosaccharides?
aldoses vs. ketoses. and length
#4) The word "Chiral" is derived from the greek word meaning "hand." How does this relate to the structure of carbohydrates?
Carbohydrates, excluding dihydroxyaetone, are chiral. each molecule has 2^n stereoisomers. Where n = the number of carbons - 2
# 5) How many D-isomers would an aldopentose have? How many total isomers?
#6) Is galactose and epimer of mannose
# 7) In an aqueous solution of D-glucose, why will there always be a very small amount of the linear form of the monosaccharide?
The ring form is more stable and is formed readily
Cyclization and stereo-isomerism
when a saccharide cyclizes, there is a new chiral center that is generated
isomeric forms of a monosaccharide that differ only in their configuration about the hemiacetal or hemiketal carbon
6 membered rings
hemiketal 5 membered ring
# 10) Why is phosphorylation of sugars beneficial to a cell?
1) Traps sugars inside of the cell 2) activates sugars for chemical processing 3) Sugar phosphates are relatively stable
A sugar can only be oxidized in its...
linear form. In a polysaccharide, the anomeric carbons not involved in the glycosidic bond are non reducing.
Q # 15 What are the structural and functional differences between homopolysaccharides and heteropolysaccharides?
Homo- one anomeric species; hetero - more than one anomeric species
contains long unbranched chains of D-glucose connected by (alpha 1->4) linkages;
contains long branched chains of D-glucose; connected by (alpha 1->4) linkages; branch points are every 24 to 30 residues with (alpha 1->6) linkages