Structural polysaccharides Flashcards
what are the two types of glucose molecules?
Alpha or beta
What is alpha glucose used for?
polymerises to form starch or glycogen, used to store energy in plants and animals
What is beta glucose used for?
Polymerises to from cellulose which is a structural material in many plants
Features of cellulose?
insoluble in water
long chain molecule
groups of cellulose are known as microfibrils
these are cemented together by another Polysaccharide to from strong cell walls (plants)
These cell walls are though and protect the cell but are still permeable to water
Why can’t most animals digest cellulose?
Enzyme that digests starch does not have an active site that fits the glycocydic bonds from beta-glucose.
Herbivorous animals often have bacteria in their stomachs that digest the cellulose
Why is glycogen an effective energy store?
can be quickly broken down to glucose for respiration
it is insoluble therefore does not exert osmotic pressure
what is lignin?
lines some cells (xylem)
makes them impermeable to water