Carbs: Starch and Glycogen Flashcards
what is the main polysaccharide store in plants
Starch
Where is starch mostly found?
leaves and storage organs
examples of storage organs
Roots/Stem/Leaves/Seeds/Fruit
How and where is starch stored in cells
It is compacted into DENSE,INSOLUBLE organs and stored in amyloplasts (organelles)
Why do storage organs have many amyloplasts
to ensure plant always has enough supply of energy
What are 2 structures starch is made of ?
Amylose
Amylopectin
Amylose structure?
long chain
of alpha glucose molecules
joined together
by 1,4 glycosidic bonds
How does amylose change shape to become more compact?
Coils up and forms a helix shape making it more compact.
How many accessible ends does amylose have
2
What is the use of the accessible ends
They are where enzyme amylase can bind and break down amylose to alpha glucose that is used in aerobic respiration
Why is amylose only broken down slowly?
it only has 2 accessible ends, that is a little.
Is Structure of amylopectin similar to amylose? What is the difference?
Yes it is similar
It has more branches coming off
Are both amylose and amylopectin stored together?
Where are they stored?
yes
both are stored togther in amyloplats
Structure of Amylopectin
Long chain
of alpha glucose molecules
joined by 1,4 glycosidic bonds
with the presence of an occasional 1,6 glycosidic bond
When counting carbon order
EG: 1,4
Where do we start from
from 3 o clock position
What is a glycosidic bond
Covalent bond
Forms between hydroxyl group of a monosaccharide and an anomeric carbon atom of another monosaccharide resuliting in the formation of a Disaccharide or polysaccharide and a water molecule
Does amylopectin have more accessible ends than amylose
yes
Why does amylopectin have more accessible ends?
presence of occasional 1,6 glycosidic bonds where enzyme can bind and break down starch to glucose to be used for aerobic respiration
What is the effect of having more accessible ends on amylopectin
More easily broken down and faster than enzymes when glucose is needed
The main polysaccharide energy store in animals
Glycogen
Found in plants?
no
Where is it mostly found?
Cells with high metabolic rate
eg: muscle and liver cells
Why do animals have glycogen but not plants
animals have higher metabolic rate than plants
animals move around much more than plants
animals have muscles and nerves and larger organs unlike plants
So why is it important to have glycogen
it is important to have a very branched molecule where it can be broken down fastly and easily by enzymes and act as a rapid source of energy used in respiration
