Polymers, proteins and amino acids

what is a monomer

small molecules that can be joined to form polymers

what is polymerisation

chemical process where monomers are linked ro each other to form polymers

what is a thermoplastic

polymer that can be melted

what is a thermoset

polymers that are cooled into shape and cant be melted again

what are the 2 types of reactions to make polymers

addition and condensation

what is an addition polymerisation and what is required

• process by which ALKENES are joined together

• catalyst and initiator is required

what holds addition polymers together

dispersion forces

what are example of polymers produced by addition polymerisation and uses

• High density Polyethene → chairs, toys, water bottles

• Low density polyethene → plastic bags , clingwrap

• polytetrafluoroethylene ( Teflon) → cookware

what are the 2 types of polyethenes and how do they differ

• High density ( HDPE) → linear in shape with little branching

• Low density ( LDPE)→ large amounts of side chains

why does teflon have unique properties

Due to C-F bonds which are stronger than C-H bonds, they have greater resistance to bonds with other chemicals = non stick

what is condensation polymerisation

polymerisation of 2 monomers with reactive functional group producing water

why must reactive functional groups be di

di allows chains to form, allowing polymer to be built

what are the characteristics of condensation polymers

• monomers have 2 reactive groups

• water is produced

what are the 2 types of condensation polymers

Polyester and polyamide

what are the properties of polyester

• have permanent net dipole around ester

• when molecules align they form dipole dipole forces

example of polyester and its use

• Polyethylene terephthalate ( PET) known as terylene

• used for bottles, bullet proof vests, clothing

what is an example of polyamide and its properties

• Nylon 6,6

• has HB as main IMF

• HB occurs between lone pair of electrons of O atom and N of NH2

• strong, stiffer and greater tensile strength compared to terylene

what is an amino acid

substance that has amino group located at any carbon and carboxylic acid located on terminal carbon

what is an alpha amino acid

has amino group and carboxylic acid linked on the same carbon known as alpha carbon

what is a zwitterion

dipolar ion where + and - charged atoms are present in same molecule

what acts as a base and acid in alpha amino acid

• COOH group gives away H+ → acid

• NH2 accepts H+ → base

why do amino acids have high MP compared to other polyamides

• α-amino acids exist as zwitterions in the solid state and the attractive force between them is ionic bonding

• which is stronger than intermolecular forces for other polar molecules

• the strong attractive forces between zwitterions requires greater energy to overcome and this results in a higher melting point

why are Amino acids soluble in water

amino acids are polar substances

what is a protein

large complex molecule made up of 50 or more amino acids

how are protiens formed

through condensation polymerisation similar to polyamides

what is the connection between 2 amino acids called

peptide bond

what is an amino acid that has lost OH or H called

residue

what is a substance made up of less than 50 amino acids called

polypeptide

what are the different types of polymers

• condensation → polyamide or polyester

• addition

what is primary protein structure

Primary level looks at order of amino acids in protein chain

what is secondary level protein structure

focuses on shape of protein → alpha helix and beta pleated sheets

how are alpha helixes formed

• form due to hydrogen bonds between hydrogen of NH2 and Oxygen from COOH

• hydrogen boding occurs within same chain and must be atleast 4 amide groups apart

how do beta pleated sheets form

• forms when hydrogen bonding between H of amide and lone pair electrons of O are adjacent to polypeptide chains

what is the tertiary structure

overall 3d shape that is sdue to different types of bonding interactions between side chains in amino acid

what are th bonding interactions in tertiary structure

• Disulfide bridge → occus when 2 SH group lose H and form covalent bond between sulfers

• Hydrogen bonding

• Ionic bonding

• Dipole-dipole

• Dispersion