3. Polysaccharides - Function of polysaccharides Flashcards
Name 3 polysaccharides?
Starch.
Glycogen/
Cellulose.
Where do cells get their energy from?
Glucose/
What do plants store excess glucose as?
Starch.
When a plant needs more glucose for energy, it breaks down starch to release the glucose.
What is starch?
A mixture of 2 polysaccharrides of alpha glucose.
Amylose and amylopectin.
How can you test the presence of starch?
Using iodine.
Orange brown colour to dark blue blac
What is amylose?
A long, unbranched chain of alpha glucose.
What is the structure of amylose like?
The angles of the glycosidic bond give it a coiled structure, almost like a cylinder.
This makes it compact, really good for storage as you can fit more into a small space.
What is amylopectin?
Long, branched chain of alpha glucose.
How does the structure of amylopectin help with its function?
As the side branches allow the enzymes to get at the glycosidic bonds easily.
Meaning glucose can be released quickly.
What helps to hold AMYLOSE’ helical structure?
Hydrogen bonds between the alpha glucose molecules.
What is starch like in water?
It is insoluble in water and doesn’t affect water potential.
Doesn’t cause water to enter cells by osmosis, making them swell.
Meaning its good for storage.
Name a reason why starch is good storage molecule?
Its too large to it can’t leave the cell.
Where do animal cells get their energy from?
Glucose.
What do animals store excess glucose as?
Glycogen.
What is the structure of glycogen?
Has lots of side branches coming off it.
Stored glucose can be released quickly, this is important for energy release in animals.
Compact molecule, good for storage.
