The 4 polysaccharides Flashcards
Why is glucose stored as starch? (2)
- Because it’s insoluble so it won’t dissolve out of the cell
- Because it is compact so it stores a lot of energy
Where is starch found?
- Seeds (rice, wheat, oats, barley
- Storage organs (potato tubers)
What is starch made of?
- Amylose
- Amylopectin
How is amylose formed?
What does amylose form?
- Formed by condensation reactions
- Forms coiled springs
How is amylopectin formed?
What does amylopectin form?
- Formed by condensation reactions between alpha glucose molecules (1, 4 or 6)
- Forms coiled springs in a branched structure
What is the difference between glycogen and amylopectin?
Glycogen has many more branches
Glycogen is extremely compact. What is an advantage of this?
It can be hydrolysed into sugar residues very quickly for respiration
Where is chitin found?
- In fungal walls
- In the exoskeletons of crustaceans and insects
Chitin is composed of a ____ compound which ___ ___ ___
Chitin is composed of a nitrogen compound which gives it strength
Why is chitin strong?
Because it is composed of a nitrogen compound which allows greater H-bonding
What are the numbers of the carbons involved in a chitin molecule?
1, 4
What must happen to the molecules of cellulose to bond Beta1,4?
To bond carbon 1 with carbon 4, every other glucose molecule must flip 180degrees
Cellulose is very strong and is a polymer of which type of glucose?
Beta
Describe the stucture of a cell wall
- Side-by-side molecules
- Held together with H-bonds to form microfibrils
What do microfibrils do?
Make up cell walls
