Carbohydrates (3.1.2) (B) Flashcards
1
Q
What are polysaccharides?
A
- Formed by the condensation of many glucose monomers
2
Q
What is the function of starch?
A
- Storage carbohydrate found in plants
- Insoluble store of glucose
3
Q
What is the structure of starch?
A
- Made up of two polymers of α-glucose: amylose and amylopectin, joined by glycosidic bonds
4
Q
Describe the structure of amylose
A
- Joined by 1, 4 glycosidic bonds forming a long, unbranched chain that coils into a helix
- Forms a compact store, enabling efficient storage of glucose
5
Q
What is the function of glycogen?
A
- Storage carbohydrate found in animal cells
- Insoluble store of glucose
- Stored in the liver and muscle cells in large amounts
5
Q
Describe the structure of amylopectin
A
- Joined by 1, 4 and 1, 6 glycosidic bonds with a long, branched structure
- Allows easy release of glucose molecules for respiration
6
Q
How is the structure of starch ideally suited to its function as a storage compound?
A
- Large molecules → so cannot leave the cell
- Insoluble → so osmotically inactive, so does not affect water potential
- Helical shape → so forms a compact store, enabling efficient storage of glucose
- Branched structure → so allows easy release of glucose molecules for respiration
7
Q
What is the structure of glycogen?
A
- Made up of α-glucose molecules, joined by glycosidic bonds
8
Q
What is the function of cellulose?
A
- Structural carbohydrate found in the cell wall of plants
- Provides structural strength to the cell wall
8
Q
How is the structure of glycogen ideally suited to its function as a storage compound?
A
- Large molecule → so cannot leave the cell
- Insoluble → so osmotically inactive, so does not affect water potential
- Branched structure → so can undergo rapid hydrolysis to release glucose
- Many free ends → so can be compacted easily storing a large amount of glucose in a small space
9
Q
What is the structure of cellulose?
A
- Consists of long, straight chains of β-glucose molecules, joined by glycosidic bonds
10
Q
How is the structure of cellulose ideally suited to its function as a structural compound?
A
- Insoluble → so osmotically inactive, so does not affect water potential
- Long, straight chains of β-glucose molecules → these chains are joined together by hydrogen bonding → to form fibrils → which provides rigidity and strength to the cell wall
11
Q
What are the similarities between starch, glycogen and cellulose?
A
- Contain glucose monomers
- Are formed during a condensation reaction
- Are insoluble and so osmotically inactive
12
Q
What are the differences between starch, glycogen and cellulose?
A
- Starch and glycogen are made up of α-glucose monomers, while cellulose is made up of β-glucose monomers
- Starch and glycogen have branched chains, while cellulose has straight chains
