Polysaccharides Flashcards
What is starch made from?
Many alpha glucose molecules
What is the biological importance of starch?
It is a carbohydrate storage in plants
What is glycogen made of?
Many alpha glucose molecules
What is the biological importance of glycogen?
It is a carbohydrate storage in animals
What is cellulose made from?
Many beta glucose molecules
What is the biological importance of cellulose?
It is in plant cell walls
What are the two polymers within starch?
Long, straight chains of amylose and branched chains of amylopectin
What is amylose made of?
Many alpha glucose molecules with glycosidic bonds between carbon 1 on one molecule and carbon 2 on another, forming an alpha 1,4 glycosidic bond
How does amylose coil up?
Into a helix due to the angle of the glycosidic bond and the structure is held together by hydrogen bonds
Why does iodine solution turn blue-black in starch?
The amylose coils trap iodine molecules, turning it blue black and this can be reversed by unraveling the coil by heating to break the hydrogen bonds
What is the structure of amylopectin?
It has many alpha 1,4 glycosidic bonds and alpha 1,6 glycosidic bonds to form branches, which occur every 25 glucose molecules
What is the structure of glycogen?
It has shorter alpha 1,4 linked glucose chains than amylopectin and many more alpha 1,6 glycosidic bonds so many more branches
Why is glycogen more compact?
So less space is needed than in plants as animals are mobile
What is the solubility of glycogen and starch?
They are both insoluble
Why are starch and glycogen insoluble?
So the water potential is not affected as if there is too much water in a cell, it will burst.
What is water potential?
Water will move from where it is less negative (pure, more concentrated) to where it is more negative (lower water concentration)
Why are both starch and glycogen held in branched chains?
So that many molecules of glucose can be readily broken off the ends of the branches and released
How does energy come from glucose?
Glucose molecules have lots of bonds which can be broken down by enzymes to release enough chemical energy to synthesise ATP
What is ATP?
Adenosine Tri-phosphate, made during respiration and is a molecule that holds small amounts of energy that can be readily released for cellular reactions.
Why do simple sugars release energy easily?
They are small simple molecules used for energy supply
What are complex carbohydrates used for?
They are more stable, compact and mostly insoluble so hey can be broken down when needed but are less ready stores of energy so are mainly used for energy storage
What does cellulose makes?
Fibres which are very stable and strong which is ideal for structural support in plant cell walls.
How is the bond between cellulose monomers drawn?
It is drawn twisted with a zigzag line
Where is cellulose found?
Only in plant cell walls
What does cellulose form?
Long straight chains which are stronger than amylose
How do hydrogen bonds form within cellulose?
Cellulose monomers contain many OH groups on the outside an then 60-70 cellulose molecules in chains which become cross linked by hydrogen bonds to form microfibrils
How are macrofibrils formed?
By microfibrils which are held together by more hydrogen bonds
