Glycosylation

Question 1

hexose example

Answer 1

glucose

Question 2

pentose exmaple

Answer 2

ribose

Question 3

aldehyde example

Answer 3

glucose

Question 4

ketone example

Answer 4

ribose

Question 5

three sugars that are stereoisomers of the same structure

Answer 5

glucose, galactose and mannose

Question 6

glycosidic linkage

• formed by what carbon
• requirement for reaction to take place

Answer 6

• formed by the anomeric carbon

- this anomeric carbon must be activated with UDP prior to the linkage being formed

Question 7

alpha maltose

Answer 7

two glucose moleculse

Question 8

alpha lactose

Answer 8

galactose and glucose

Question 9

sucrose

Answer 9

fructose and glucose

Question 10

amylopectin vs amylose

Answer 10

amylose is a straight chain polysaccharide whereas amylopectin is a branched polysaccharide

Question 11

glucose vs glycogen

Answer 11

• glucose is a single saccharide
• glycogen is a branched polysaccharide with alpha 1,4 linkages between the straight chain monomers and alpha 1,6 linkages at the branch points

Question 12

chondroitin

Answer 12

• GAG

- bone, cartilage, cornea formation

Question 13

keratin sulfate

Answer 13

• GAG

- cornea connective tissue

Question 14

dermatan sulfate

Answer 14

• GAG

- binds LDL to plasma walls

Question 15

heparan sulfate

Answer 15

• GAG

- aortic wall, basement membrane

Question 16

heparin

Answer 16

• GAG

- anticoagulant

Question 17

hyaluronic acid

Answer 17

• GAG
• cell migration, lubricant
• not covalently attached to a protein

Question 18

GAG general structure

Answer 18

• long linear polysaccharides
• repeating disaccharide units
• considerable negative charge (including sulfate)

Question 19

glycolipids
-example
-

Answer 19

• gangliosides

- come from sugar modifications of lipids

Question 20

glycation

-HbA1c

Answer 20

• non-enzymatic glycosylation of proteins
• formation of HbA1c
• simple chemical reaction of sugar and protein side chains

Question 21

enzymatic glycosylation (conjugation)

• added to
• requirement
• specificity

Answer 21

• occurs to add sugars to other sugars, proteins, or lipids
• requires prior activation of sugar which is accomplished by formation of sugar nucleotides
• enzymes are specific for each different sugar being added as well as the accepting sugar molecule

Question 22

where is the sugar of glycoproteins located

Answer 22

-except for O-GlcNac, they are located either in the lumen of the ER, the extracellular side of the plasma membrane , or secreted

Question 23

O-linked glycoprotein

Answer 23

• largely built on Ser/Thr residues

- built one sugar at a time

Question 24

N-linked glycoprotein

Answer 24

• built on Asp
• initially added to the protein in a 14 sugar block
• constructed on a dilochol phosphate lipid
• initial transfer to N is usually cotranslational in the ER

Question 25

similaritry between construction of N and O linked glycoproteins

Answer 25

-they are both processed as the glycoprotein traffics from the Er through the golgi

Question 26

glycoprotein and polysaccharide breakdown

Answer 26

- occurs in the lysosome with the help of many different types of enzymes - when these enzymes fail you can get lysosomal storage diseases (mucopolysaccharidoses)

Question 27

pompe disease

Answer 27

single lysosomal enzyme disease defect

Question 28

proteoglycans

Answer 28

- made of over 90% sugar - important structural components - part of the matrix that makes up tissue structure - found in cartilage, dentin or predentin - hydrated so they can provid cushion - charged so they can bind substances like growth factors and chemokines.cytokines

Question 29

biological recognition

Answer 29

- often involves glycosylation - protein recognition of carbohydrate structures usually involves a lectin domain - deficiency disease 2)

Question 30

examples of uses of carbs in major bodily functions - blood type - infection - cell contacts

Answer 30

carbohydrate structures underlie the differences in ABO blood type groups, contribute to the ability of viruses (flu) or bacteria (H. pylori) to infect, and mediate cell-cell contacts (leukocyte adhesion

Question 31

chaperon mediated protein folding

Answer 31

-facilitated by carbohydrate binding in the ER

Question 32

mannose-6-phosphate

Answer 32

-mediates tafficking of lysosomal enzymes