proteins Flashcards
what is the general structure of an amino acid?
a carbon attached to a hydrogen, amine group, carboxylic group and side chain (R group)
what is an amine group?
a functional group found in amino acids and made up of a nitrogen atom and two hydrogens
what is a carboxylic group?
a functional group found in amino acids and made up of a carbon, oxygen and hydroxide
what is a dipeptide?
two amino acids joined together with a peptide bond by a condensation reaction
what does the primary structure of proteins include?
chains of amino acids joined together by peptide bonds
what does the secondary structure of proteins include?
hydrogen bonds between carboxylic and amine groups which form alpha helixes or beta sheets
what does the tertiary structure of proteins include?
a precise 3D structure formed by folding up alpha helix or beta sheet secondary structure
what does the quaternary structure of proteins include?
multiple polypeptide chains bound together with additional prosthetic groups (which are non-protein)
where are hydrogen bonds formed in proteins?
between carboxylic and amine groups, or polar R groups
where are disulphide bridges formed in proteins?
between cystein molecules containing sulphur
where are ionic bonds formed in proteins?
ionised amine and carboxylic groups, or oppositely charged R groups
where can you find hydrophobic interaction in proteins?
between non-polar side chains
what are the four types of protein side chain interaction?
hydrogen bonds, disulphide bridges, ionic bonds and hydrophobic interaction
what is the structure of haemoglobin?
two alpha polypeptide chains and two beta chains, held together with weak forces, each with an iron-containing prosthetic haem group
what is a globular protein?
a protein which forms a spherical mass with a specific 3D shape and all the hydrophillic groups on the outside
what is a fibrous protein?
a protein with forms long chains or fibres for structure (skin, teeth, bones, etc)
what type of protein are enzymes?
globular
how many times do enzymes increase reaction time by?
108 - 1011 times
what is the allosteric site of an enzyme?
where non-competitive inhibitors bind, which change the shape of the active site
what are the two types of co-factors?
prosthetic groups and co-enzymes
what is the induced fit hypothesis?
when substrate binding causes a change in the enzyme’s conformation, the active site is moulded to be suitable for the reaction, bonds stretched
