Polysaccharides Flashcards
What monosaccharide is the polysaccharide glycogen made of?
Alpha glucose
What monosaccharide is the polysaccharide starch made of?
Alpha glucose
What monosaccharide is the polysaccharide cellulose made of?
Beta glucose
What is the role of starch?
Energy store in plants
What is the role of glycogen?
Major carbohydrate storage product in animals
Help regulate blood glucose sugar levels
What is the role of cellulose?
Provide rigidity to the plant cell→strength in cell walls
What causes the molecules to form branches in starch?
1,6 glycosidic bonds
Why is starch being insoluble important?
• No osmotic effect - does not affect water potential
• does not leave cell
Why is it important for starch to have a compact structure?
Coiled/helical/spiral so a lot can be packed in a small space
Why is starch being in a long/large chain helpful to its function?
So the starch does not leave cell
Why is it important that starch has a branched chain?
Gives many ends for enzymes to hydrolyse/remove glucose quickly for respiration
How do you test for the presence of starch?
• Add iodine
• look for blue/black colour
How can we measure the actual size of starch grains drawn in a diagram from a microscope?
The actual size ( um ) = image ( mm ) divided by magnification (x)
How does the structure of glycogen differ from that of starch if they are both made of alpha glucose?
It has more 1,6 branches
What is the difference in the roles of glycogen and starch?
Glycogen stores glucose in animals whereas starch stores glucose in plants
What is the name of an OH group?
Hydroxyl
What must happen to enable the OH groups of the beta glucose to get close enough to react to make a glycosidic bond?
Alternative glucose molecules are rotated 180°
What cellular structure is made out of cellulose?
Plant cell walls
How do microfibrils form?
Many hydrogen bonds between OH groups on different parallel cellulose molecules form cross links between adjacent chains, forming micofiblis
The beta 1,4 bond is difficult to break and so resists digestion by enzymes, so how do herbivores such as cows manage to digest grass?
• Only bacteria make cellulase, the enzyme needed to digest cellulose
• Bacteria live in the digestive systems of herbivores
