1.4 Starch, glycogen and cellulose Flashcards
where can starch be found?
give a common example.
many plants in the form of small granules or grains.
e.g chloroplasts
why does osmosis not occur in starch and glycogen?
because they are insoluble
what is the main role of starch?
energy storage
name the five ways in which starch is suitable for its role.
insoluble large molecule compact branched hydrolysed form is an energy source
when hydrolysed what does starch form?
why is this useful?
a-glucose, an energy source for respiration
what effect does starch’s branched form have on its ability to break down?
many ends which can be acted on by enzymes which break down the chain into monosaccharides.
what effect does being insoluble have on starch?
does not draw water into the cell
where can starch be found?
In what form?
many parts of a plant in small grains.
what is the importance of starch?
it forms a major energy source in most diets and is an important component of food.
Are the chains branched or unbranched in starch?
can be both
describe the two chains present in starch.
Amylose - a long unbranched chain of a-glucose with a coiled structure
Amylopectin - long branched chain of a-glucose
what is cellulose a major component of ?
plant cell walls
what effect does cellulose have on the cell wall of a plant?
provides rigidity to the cell wall.
stops the cell from bursting
how does cellulose stop the plant cell from bursting?
it stops the cell wall from bursting by exerting an inward pressure that stops any influx of water
how is cellulose made?
monomers of b-glucose
In cellulose are the chains branched or unbranched?
unbranched and straight.
describe the structure of cellulose.
straight unbranched chains run parallel to each other allowing hydrogen bonds to form cross-linkages between adjacent chains.
what effect do the hydrogen bonds have on the cellulose molecule?
each hydrogen bond adds very little strength but the overall number of them makes the molecule very strong.
how are cellulose molecules grouped together?
grouped together to form microfibrils, which in turn are arranged to form fibre groups.
where and how is glycogen stored?
small granules in the muscles and liver
to whom is glycogen the most important?
animals with a higher metabolic rate
where can glycogen be found?
animal cells and bacteria
what is the importance of glycogen?
major carbohydrate storage product of animals
what does having ‘branches’ mean for glycogen?
enzymes can work quickly on the ends of the branches, this hydrolyses glucose molecules that can be used in respiration
what is the main role of glycogen?
energy storage
How is glycogen suitable for its role?
insoluble
compact
highly branched
describe the effects of glycogen being insoluble.
does not draw water into the cell
does not diffuse of the cell
Glycogen is compact, what does this mean?
a lot can be stored in a small place
glycogen is highly branched, how does this help it break down?
being highly branched allows the ends to be worked on by enzymes allowing glycogen to be broken down into glucose monomers
