polysaccharides

Question 1

what is starch/amylose composed of

Answer 1

alpha 1-4 glucose molecules

Question 2

what is glycogen composed of

Answer 2

alpha 1-4 glucose molecules with more branch points connecting alpha 1-6

Question 3

what is amylopectin

Answer 3

it is the more highly branched form of amylose, it branches at 1-6

Question 4

what are the alpha linkages discussed in class

Answer 4

glycogen, starch (also amylopectin and amylose)

Question 5

what is cellulose composed of

Answer 5

glucose molecules in beta 1-4

Question 6

how are starch, glycogen, and cellulose different

Answer 6

they are all glucose molecules but vary how they connect

Question 7

what is chitin comprised of

Answer 7

N-acetylglucosamine residues in beta(1-4) linkages

Question 8

what polysaccharides are hydrophobic? why?

Answer 8

chitin and cellulose, they have beta 1-4 connections which gives them a linear structure and allow them to form intermolecular hydrogen bonds with other molecules. this allows them to form sheets and layers that are fully saturated and unable to form hydrogen bonds

Question 9

what polysaccharides are hydrophillic? why?

Answer 9

amylose, starch, glycogen

they have alpha (1-4) bonds which makes them form a helical structure. Not all of the hydroxy groups can participate in hydrogen bonding with themselves, so they are able to form hydrogen bonds with water molecules

Question 10

what are glycosaminoglycans

Answer 10

they are heteosacchairdes with one monomer of either N-acetyl-glucoseamine or N-acetyl-galactoseamine

the other monomer is a negatively charged uronic acid (c6 oxidation) or a sulfate ester

Question 11

what is heparan

Answer 11

it is a glycoaminoglycanthat has alternating residues of D-glucuronic acid and N-acetylglucoseamine

Question 12

What is heparan sulfate

Answer 12

it is a glycoaminoglycan that has nonrandom arrangements of suldated and nonsulfated sugars

Question 13

what is peptidoglycan

Answer 13

it is a rigid component of cell walls

Question 14

what is peptidoglycan made of?

Answer 14

it is made of a heteropolymer of alternating (B1-4) linked N-acetylglucosamine and N-acetylmuramic acid residues

it is cross linked by short peptides

Question 15

why is the cell wall of bacteria so strong

Answer 15

it is made of beta(1-4) linked N-acetylmuramic acid and N-acetylglucoseamine residues

Question 16

how do we test for endotoxicity

Answer 16

Limulus-Amebocyte Lysate endotoxin test with horseshoe crabs

Question 17

what is the ecm comprised of

Answer 17

glycosaminoglycans

Question 18

what is a glycan

Answer 18

mainly comprised of sugars with some protein, lipid, etc attachement

Question 19

what is a glycoprotein? where is it found?

Answer 19

one or several sugar components joined covalently to a protein

it is found on the outer face of the plasma membrane

Question 20

what is a glycolipid

Answer 20

it is a lipid with a hydrophilic oligosaccharide head

Question 21

where are carbohydrates attached in glycoproteins

Answer 21

they are attached at the anomeric carbon

Question 22

what is the role of glycoproteins?

Answer 22

they are involved in protein-protein recognition

Question 23

what are proteoglycan aggregates

Answer 23

they are large hyaluronan backbones with proteoglycan monomers attached via link proteins

Question 24

how are proteoglycan aggregates involved in the ECM

Answer 24

aggregates interact strongly with collegen in the ECM of collagen

Question 25

what is fibronectin?

Answer 25

it is a multifunctional protein that acts as an extracellular glue to bind to fibrin, heparan sulfates, collagen, and integrins

Question 26

what are integrins

Answer 26

they are proteins that mediate signalling between cell interior and ECM molecules

Question 27

how are sugars involved in the extracellular matrix

Answer 27

glycosaminoglycans make up the fibers with N-actetyl glucosamine/galactosamine and charged uronic or sulfate esters they are also in involved as glycoproteins in proteoglycan aggregates

Question 28

what are the two ways that oligosaccharides are attached to glycoproteins

Answer 28

they can be O-linked or N linked

Question 29

what does an O linkage mean in glycoproteins

Answer 29

it means that the anomeric carbon in sugars are attached to the OH of a serine or threonine group

Question 30

what does an N linkage mean in glycoproteins

Answer 30

It means the N-glycosyl bond joins the anomeric carbon of a sugar to the amide nitrogen of an asparagine residue

Question 31

why are not all serine residues glycoslyated?

Answer 31

enzymes recognize specific protein sequences and add to them

Question 32

what are the roles of adding oligosacchairdes to proteins

Answer 32

they influence the folding and stability of proteins they allow specific recognition by other proteins

Question 33

what is mucin?

Answer 33

they are secreted or membrane glycoproteins that can contain large numbers of O-linked oligosaccharide chains

Question 34

what are glycomics

Answer 34

they are systemic characterization of all carbohydrate components of cells/tissues

Question 35

what is glycoslyation

Answer 35

it is when sugar trees are added through a regulated means by enzymes

Question 36

what is glycation?

Answer 36

it is when sugars are added by random chemical reactions

Question 37

what is the malliard reaction, why is it bad?

Answer 37

the malliard reaction is a reaction that occurs between sugars and proteins, it can create harmful side products called AGEs

Question 38

how does cooking steak contribute to cellular aging lol

Answer 38

compounds formed by the maillard reaction result in the formaiton of AGEs which contribute to cellular aging

Question 39

why is diabetes affected by the malliard reaction

Answer 39

normally glucose is cleared by insulin in theblood, but in diabetes the sugar stays in the blood for too long and forms harmful AGEs