polysaccharides

what are examples of polysaccharides

cellulose, starch and glycogen

what are these polysaccharides polymers of ?, and how are they formed

they are polymers of glucose, formed by the joining of glucose molecules during a condensation reaction.

what condensation is glycogen and starch formed by

condensation of an alpha glucose

what condensation is cellulose formed by

condensation of a beta glucose

State the properties of polysaccharides

• Do not taste sweet and are insoluble in water

• are non reducing sugars- give a negative result on the benedict test

• fuction as storage(starch and glycogen) or structural molecules (cellulose)

what is starch

the storage carbohydrate found in plants

what does starch consist of

Long, branched chains of alpha glucose joined together by a glycosidic bond formed as a result of a condensation reaction

what is starch stored in

stored in starch grains in the cytoplasm of plant cells

why is starch ideally suited to its function ( STRUCTURE AND PROPERTIES OF STARCH)

• it is larg4e so it cannot cross the cell surface membrane and leave the cell

• it is insoluble therefore osmotically inactive (does not draw water into the cell by osmosis which could cause damage)

• molecule has a helical shape forming a compact store

• it is branched so glucose is easily released for respiration

how can starch be hydrolysed

by enzyme amylase or heated with acid

what is glycogen and where is it found

storage carbohydrate found in the cytoplasm of animal cells

how is glycogen formed

formed by the condensation of alpha glucose

In mammals where is glycogen stored

stored in the liver and muscle tissues (large amounts)

state the properties and structure of glycogen

• it is insoluble therefore osmotically inactive

• more branches than starch- can be hydrolysed more rapidly to release glucose for respiration

where is cellulose found and what does it provide

found in the cell wall of plants which provides rigidity and shape to the cell

what does the rigidity and shape to the cell in the cellulose help prevent

it prevents the plant from bursting (osmolysis)

what polymer is cellulose made from

C3ellulose is a polymer of beta glucose joined together by a glycosidic bonds

where are these glycosidic bonds formed

formed in condensation reactions to produce long straight chains of beta glucose molecules

describe the formation of beta glucose monomers in cellulose

in cellulose every other beta glucose monomer is inverted

what is the structure of cellulose

made from B-glucose chains. hydroxyl groups project from the chains and form hydrogen bonds with adjancent chains

what do hydrogen bonds between cellulose chains form

form microfibrils which provide strength

what is the fuction of cellulose microfibrils

they provide strength to the cell wall, helping plant cells maintain their shape