Carbs - Cellulose

Question 1

What is made from cellulose?

Answer 1

The cell wall of plants

Question 2

What is cellulose am example of?

Answer 2

A structural polysaccharide

Question 3

What does cellulose do?

What does it make the cell?

Answer 3

It is very strong and stops plant cells bursting when too much water enters by osmosis

It makes the cell turgid

Question 4

What does the turgidity of cellulose provide?

Answer 4

Enough strength to each cell to support the whole plant

Question 5

What is cellulose composed of?

It’s structure

Answer 5

It’s composed of many thousands of ß-glucose molecules joined together by 1,4 glycosidic bonds

Question 6

What must happen to be able to for, the 1,4 glycosidic bonds?

Answer 6

Each ß-glucose molecule must be inverted by 180° from the previous molecule

Question 7

Why does each ß-glucose molecule need to be inverted?

Answer 7

The inversions keep cellulose from colliding and results in a long, straight chain

Question 8

What does straight cellulose chains allow?

Answer 8

It allows many chains to run parallel to each other

Question 9

What does having chains running parallel to each other result in?

What forms between the hydroxyl groups?

What does this result in?

Answer 9

Hydroxyl groups being in close proximity

Hydrogen bonds form between the hydroxyl groups on adjacent chains

Which results I’m cross-linking between cellulose chains

Question 10

How is cellulose strong?

Answer 10

While each individual hydrogen bond is weak the many thousands of hydrogen bonds collectively make cellulose very strong

Question 11

How are stronger fibres formed?

Answer 11

The hydrogen bonds that cross-link the cellulose chains allow the chains to form into stronger fibres

Question 12

Fibres

How is extra strength provided to the plant cell wall?

(4)

Answer 12

• cellulose chains bundle together to form microfibrils
• microfibrils bundle together to form larger fibres called macrofibrils (fibres)
• macrofibrils (fibres) wrap around plant cells in multiple layers at different angles
• the wrapping fo the strong cellulose fibres around the plant cell provides extra strength

Question 13

Cellulose if the main component of plant walls. What does it make it in the world?

Answer 13

The most abundant organic material

Question 14

Why is cellulose not an easily digestible food source?

Answer 14

Because it’s very hard to break down by hydrolysis

Question 15

Why is it hard to break cellulose down by hydrolysis?

Answer 15

Because most animals lack the cellulase enzyme needed to break the 1,4 glycosidic bonds between ß-glucose molecules

Question 16

What type of animal has a way to break down cellulose?

Answer 16

Herbivores

Question 17

How do herbivores break down cellulose?

Answer 17

They have a symbiotic bacteria in their guts which produces the cellulase enzyme

Question 18

How does being able to digest cellulose benefit herbivores?

Answer 18

They can digest a larger portion of their diet and gain more energy

Question 19

Why is cellulose important to the human diet?

Answer 19

Because it provides the fibre needed to keep the digestive system healthy