Carbohydrates Flashcards
Amylopectin
a branched polymer, with an α-1,6-glycosidic bond for every 30 α-1, 4-glycosidic bonds.
Amylose
a linear polymer of glucose units linked by α-1,4-
glycosidic bonds.
Glycoproteins
The protein is the largest component by weight. Glycoproteins play
a variety of roles including as membrane proteins.
Proteoglycans
The protein is aYached to a par<cular type of polysaccharide called a glycosaminoglycan. By weight, proteoglycans are mainly carbohydrate. Proteoglycans play structural roles or act as lubricants
Mucins or mucoproteins
Like proteoglycans, mucins are predominantly carbohydrate. The protein is characteristically attached to the carbohydrate by N- acetylgalactosamine. Mucins are often lubricants.
In all classes of glycoproteins, carbohydrates are attached to the nitrogen atom in the side chain of ____
asparagine (N-linkage)
In all classes of glycoproteins, carbohydrates are attached to the oxygen atom of the side chain of ____
serine or threonine (O-linkage).
Glycosaminoglycans
are composed of repeating units of a disaccharide, one of which is a derivative of an amino sugar and one of which carries a negative charge, either as a carboxylate or sulfate.
Sucrose
a-1,B-2
Lactose
B-1,a-4
Maltose
a-1,a-4
glycogen
lined by α-1, 4-glycosidic bonds, with branches formed by α-1, 6-glycosidic bonds every 10 glucose units.
All N-linked polysaccharides consist of
a common pentasaccharide core, consisting of three mannoses, a six-carbon sugar, and two N-acetylgalactosamine units.
In blood group A
N-acetylgalactosamine is added to the O by a specific glycosyltransferase
In blood group B
galactose is added by another transferase
Some viruses gain entry into cells by first binding to carbohydrates on the cell surface.
The influenza virus binds to oligosaccharides composed sialic acid and galactose.
* The viral protein hemagglu<nin is responsible for carbohydrate binding.
