carbohydrates (lecture 5)

Question 1

Glycosidases:

Answer 1

cleave bonds between monosaccharides, releasing energy

Question 2

glycosyltransferases

Answer 2

catalyze the formation of glycosidic bonds. aka, this is the enzyme that sticks the individual sugars together

Question 3

proteoglycans

Answer 3

type of glycoprotein that is mostly sugars with one core protein

Question 4

mucins

Answer 4

type of glycoprotein that is amino sugar derivatives. lubricants, found in lungs

Question 5

what role does UDP play?

Answer 5

UDP provides the energy for the transfer of the sugar onto a growing chain of sugars.

Question 6

why are glycogen/starch important- what do they do?

Answer 6

energy storage. they are storage forms of glucose

Question 7

cellulose is what types of linkages, and why cant we digest it?

Answer 7

beta 1,4. humans cant digest beta linkages

Question 8

starch/glycogen are what types of linkages

Answer 8

alpha 1,4 and every 10th is alpha 1,6

Question 9

name the ways carbs can be modified

Answer 9

phosphorylation, sulfation, or adding amine/acetyl/acid groups

Question 10

N-linkage

Answer 10

a modified glucose molecule linked by asparagine to a nitrogen, usually a nitrogenous amino acid/carboxamide

Question 11

how do glycosidic bonds form

Answer 11

condensation rxns- remove an H20, take the OH from the C1

Question 12

what is the ‘non reducing’ and ‘reducing’ end of a glucose?

Answer 12

C1 is the reducing end. reacts with oxidizing agents. CH2OH is the non-reducing end

Question 13

pyranose

Answer 13

glucose in ring form (hexagon, one oxygen)

Question 14

furan

Answer 14

fructose in ring form (pentagon, 1 oxygen)

Question 15

hemiacetal

Answer 15

OH-c-OH-R-H

Question 16

hemiketal

Answer 16

OH-C-OH-R-R

Question 17

O-linked; which amino acids?

Answer 17

serine, threonine

Question 18

what’s the structure of N-linked carbs

Answer 18

the N-linked have a common core of 9 mannose residues that may be trimmed and further glycosylated.

Question 19

structure of O-linked carbs

Answer 19

O-linked are shorter than N-linked carbs but more variable in sequence

Question 20

can glycoproteins be both n-linked and o-linked?

Answer 20

Glycoproteins can have both O- and N-linked chains within the same molecule.

Question 21

Functions of glycosylations

Answer 21

a. Phosphorylated mannose : used to send hydrolytic enzymes to the lysosomes where they function. b. Cell adhesion/recognition c. Protection against protease degradation and clearance at the kidney

Question 22

If the mannose gets a phosphate group attached to it, this acts as a signal to direct the enzyme to the ___

Answer 22

lysosome

Question 23

how do blood types relate to carbs

Answer 23

blood groups are based on protein glycosylation patterns. aka the way the glycoproteins arrange themselves determine your specific proteins and antibodies that u recognize

Question 24

the 3 uses for sugars:

Answer 24

Protection Recognition (use it to bring to lysososme) Attach cells together

Question 25

lectins

Answer 25

lectins are specific carbohydrate- bidning proteins which recognize specific sugars/ linakges on other glycoproteins.

Question 26

structure of proteoglycins (discuss the sugars)

Answer 26

Carbohydrate chains on Proteoglycans are regular heteropolymers that alternate two sugars (one is an acid and one is an acetylated amino sugar) forming a long chain.

Question 27

The ____on one cell recognize and bind to carbohydrates on another cell with multiple weak interactions. Such binding facilitates cell-cell interaction.

Answer 27

lectins

Question 28

how is the flu an example of lectins at work?

Answer 28

Another example of lectins in action: Flu virus has a receptor for sialic acid . Recognizes sialic acid residues for a protein on our cell surface. Sticks in penetrating molecules that disrupt the cell and infect you. Protein recognizign a sugar chain on cell surface

Question 29

this is the most prevalent component of cartilage

Answer 29

chondroitin

Question 30

how does cartilage work as a shock absorber

Answer 30

Cartilage is mostly extra cellular matrix molecules like these (see notebook for branching diagrams ) one little cell secreting all this stuff around it- these chondroitins, hyaluronic acids with branches, etc . This creates a cushion around the cells. Helps give cells structure.

Question 31

The structure of glycogen has all of the following characteristics except:

• Glucose monomers linked from the alpha position of C1 hydroxyl to C4 hydroxyl on an adjacent glucose monomer
• Branch points with glucose monomers linked alpha 1,6 and alpha 1,4 to the same glucose monomer
• After a branch point, glucose monomers might be sulfated or aminoacetylated
• The branching pattern provides multiple ends with the nonreducing side available but the only reducing end present is on the glucose that initially started the branching pattern.

Answer 31

After a branch point, glucose monomers are NOT sulfated or aminoacetylated. ONLY PROTEOGLYCANS ARE SULFATED OR ACYLATED

Question 32

Anomers:

Answer 32

alpha vs beta formations of molecules