Cellulose

Question 1

What is Pectin?

Answer 1

Hydrophilic gel-forming component.

It is composed of heterogeneous polysaccharies

Question 2

__________ ____ form the main backbone of pectin and is important for its hydrophiilc properties.

Answer 2

Galacturonic acid

Question 3

What type of ion help pectin form a network by ionic bonds?

Answer 3

Ca2+

Question 4

What is hemicellulose primarily made of?

Answer 4

Five carbon sugars

Question 5

What are two common hemicelluloses?

Answer 5

Xyloglucan

Glucuronoarabinoxylan

Question 6

Wat is the primary role of hemicelluloses?

Answer 6

cross-link cellulose microfibrils on cell walls

Question 7

What are the four steps of the life of a polymer?

Answer 7

Synthesis
Deposition
Assembly
Modification

Question 8

What is the self-assembly model?

Answer 8

Isolated celluloses can be dissolved in strong solvents, and stable fiber can be formed spontaneously. i.e., manufacturing of rayon

Question 9

What is the enzyme mediate assembly model?

Answer 9

Xyloglucan endoglucosylase can cut xyloglucan and add a new xyloglucan molecule in vitro

Question 10

What are the components of the primary cell wall?

Answer 10

Cellulose
Hemicellulose
Pectin

Question 11

What are the additional non-carbohydrate components?

Answer 11

Lignin - more abundant in secondary cell walls

Structural proteins - focus only on expansion protein

Question 12

What is the precursor of lignin monomers?

Answer 12

Amino acids

Question 13

What is creep?

Answer 13

The irreversible extention of cell walls which occurs by slippage of cell wall polymers relative to one another

Question 14

What are the two types of glucose polymer structures?

Answer 14

Starch or amylose (alpha glucose form)

Cellulose (beta glucose form)

Question 15

What bond tightly packs cellulose to form a microfibrils?

Answer 15

Hydrogen bonding

Question 16

How thick are are cellulose?

Answer 16

1-10 nm width

Question 17

What dose using SEM and freeze-fracture help you to examine?
What did they discover using SEM?

Answer 17

Surface topology

Rosette patterns

Question 17

What dose using SEM and freeze-fracture help you to examine?
What did they discover using SEM?

Answer 17

Surface topology

Rosette patterns

Question 18

Lignin is ____ and ____ linked with polysaccharides

Answer 18

Intertwined

covalently linked

Question 19

What is the casparian strip model?

Answer 19

CASP1 protein organizes membrane proteins at the casparian strip

Question 20

What protein suggests that lignin is not randomly deposited.?

Answer 20

ESB1 (enhanced suberin 1 protein)

Certain orientation occur when this protein is present. It is essential for proper lignification

Question 21

What are two important considerations for cell wall expandability?

Answer 21

Tip growth (growth at the apical dome)
Important for root hairs and pollen tubes) 

and diffuse growth (equal directions). Most cells in multicellular plants grow by diffuse growth

Question 22

What is the role of MT in cellulose microfibril

Answer 22

It dictates the orientation of newly deposited cellulose microfibrils.

Question 23

What are the two observations relevant to cell wall expansion?

Answer 23

1) Cell wall loosening is enhanced at acidic pH

2) Drug fusicoccin treatment on plants enhanced cell wall loosening. Fusicoccin is known to activate H+ ATPases on PM

Question 24

What is the instrument used to experimentally measure cell wall expandability

Question 24

What is the instrument used to experimentally measure cell wall expandability