Proteins
Cards (14)
- globular proteinscompactsphericalsoluble in water -> orientation of hydro-interactionseasily transported and involved in metabolic reactionsfolding into specific shapes -> enzymes and active sites, and receptors for antigens
- conjugated proteincontain a prosthetic group
- haemoglobincarries oxygen as oxyhaemoglobinquaternary structure -> 4 polypeptide chains2 a-globin and 2 b-globin4 globin chains held by disulfide bondshaem group (fe2+) holds oxygen
- function of haemoglobintransport oxygen around the bodysoluble -> more efficient travel in the blood than oxygen by itselfeach oxygen binds and alters the quaternary structure making the next molecule easier to bind
- insulinproduced by b-cells in the pancreascontrol of blood glucosetwo polypeptide chains held by disulfide bondsspecific structure to membrane receptors
- pepsinenzymesuited to acidic conditions in the stomach
- fibrous proteinslong polypeptide chains with cross links between chains due to hydrogen bondinginsoluble due to the presence of increased hydrophobic R groupshighly repetitive amino acid sequence -> organised structure
- (f) collagenflexible -> connective tissuesmany hydrogen bonds -> increase tensile strengthinsoluble -> high length increases time taken to dissolvepresent in artery walls to withstand pressure
- (f) keratinstronglarge amounts of the amino acid cysteine which increases the amount of disulfide bondsfound in finger nails and hair
- (f) elastinconnective tissueblood vessels -> stretch and recoil to each pulse response
- primary structuresequence of amino acids with peptide bonds between them
- secondary structurebeta pleated sheet or alpha helixhydrogen bonds
- tertiary structureionic and disulfide bondshydrophobic and hydrophillic interactions
- structure of collagenpeptide bonds between amino acidsevery third amino acid is glycinecoils into a helixthree polypeptide chainshydrogen bonds between the chainsforms fibrils