Carbohydrates II

Question 1

Hawthorne form

Answer 1

cyclic form with an anomeric carbon

Question 2

Fischer form

Answer 2

straight chained and has no anomeric carbon.

Question 3

sucrose (disaccharide)

Answer 3

(glucose + fructose)

Question 4

Lactose (disaccharide)

Answer 4

(glucose + galactose)

Question 5

Maltose (disaccharide)

Answer 5

2 glucose

Question 6

Glycosidic bond

Answer 6

A type of covalent bond that bonds a carb to another group. Most common type of linkage in higher order saccharides

Question 7

Glycoprotein

Answer 7

proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. Attachment of the oligosaccharide is by two methods - N-linked oligosaccharides in glycoproteins are attached to the R-group amine of asparagine in a protein. This occurs in the endoplasmic reticulum and Golgi apparatus. O-linked oligosaccharides in glycoproteins are attached to the R-group hydroxides of serine/threonine in a protein. This occurs only in the Golgi apparatus.

Question 8

Most common polysaccharides

Answer 8

glycogen (energy storage in animals), cellulose (structural integrity in plants), starch (energy storage in plants), chitin (exoskeleton of insects).

Question 9

homopolymers

Answer 9

Polysaccharides that contain only one sugar residue

Question 10

heteropolymers

Answer 10

polysaccharides that contain more than one sugar residue

Question 11

enzyme cellulase

Answer 11

required to digest the beta 1-4 bonds of cellulose. Most animals do not contain cellulase.

Question 12

Lectins

Answer 12

proteins that bind to specific carbohydrates. They are called phytohemagluttinins in plants. They are used 1) in the immune system to recognize bacteria non-specifically and 2) by bacteria/viruses to attached to specific structures on the surface of cells to assist in attachment to the cell for the purpose of injecting nucleic acid. The flu virus enters the cell in this way.

Question 13

glycolipids

Answer 13

lipids attached to carbohydrates. Common ones include sphingolipids, such as cerebrosides (attachment of one sugar) and gangliosides (attachment of complex carbohydrates).

Question 14

Glycosaminoglycans

Answer 14

polymers of pairs of modified sugars. At least one of the sugars of each pair is negatively charged, such as glucuronic acid, creating a polyanionic compound.

Question 15

Proteoglycans

Answer 15

created when glycosaminoglycans are attached to peptides.

Question 16

Glycosylation patters of glycoproteins

Answer 16

typically have a common core at the point of attachment to the protein and then the exterior oligosaccharide structures vary in composition.

Question 17

Hyaluronan

Answer 17

a proteoglycan (the glycosaminoglycan attached to it is hyaluronic acid) that is important in synovial fluid to lubricate joints.