Biology 4A - USES

how do plants provide fiber

from cellulose walls - tough but easily broken down due to pectate

what is cotton

a type of pure fiber packed around a seed… they however need to be spun into usuable threads

how are plants able to survive difficult conditions

amyloplast stores

why are synthetic fibers not desirbable and are desireable

cheap, hardwearing, but non-breathable and non-reneawble, does not absorb liquid

describe the structure of wood

composite material made up of lignified cellulose fibers embedded in hemicellulose

what are the properties of wood

• resistant to compression

• doesn’t crack due to flexibility of intermeshing cellulose fibers

• strong

• carbon neutral

• good insulator

how is paper made from wood

• made my soaking wood in an alkali and pressing the pulp into a frame

what are the different methods of processing fibers (breaking down the pectate matrix)

• retting : natural decomposers breaking down the material around fibers

• chemicals and enzymes used in industry

what are the pros and cons of synthetic polymer plastics

they are soft, flexible, low m.p. and they can cause environmental problems

what are causes for plastic pollution

they are inert, non-biodegrable, only some can be melted and recycled

what are bio plastics and why are they good

they are sustainbale made from plants

biodegradable

burning releases CO2 which is better than CH4 when biodegrading so it is often burnt

what is cellulose - based plastic, thermoplastic starch and PLA

C- made from wood pulp

T- made from starch mixed with other compounds

P - biodegrable made from sugar cane is stiff