P4- Describe the structural features of an enzyme:
M3 – Explain how the rates of enzyme reactons are afectee by changes in temperature:
D3 – Explain why enzyme actiity is afectee by the PH:
In this assignment I will explain how the rates of enzyme reactons are aaected dy changes
in temperature and I will also explain why the enzyme actiity is aaected dy the P P I will
also descride the structural features of the enzymeP
Structure of the enzymes:
First of all, enzymes are proteins which are specialised to carry out a partcular roleP The
enzyme molecules haie an actie siteP They are usually spherical decause of the tght folding
of the polypeptde chainsP They are also soludle and they ofen haie roles in the
metadolismP An example could de that some enzymes are specialised in dreaking large food
molecules, dut there are also enzymes which specialise in the synthesis of the small
molecules into large onesP Some of the enzymes could act as diological catalystsP They are
protein molecules with an actie site which has a
specifc shapeP The actie site of an enzyme is
where the sudstrate molecule dinds to the
enzymeP It has deen proien that the enzymes
are iery specifc decause of their specifc tertary
structureP
The enzymes also haie side chains which help to
stadilise the structureP One of the amino acid
side chains is called ‘amine group’ which is the
group of the protein which contains a nitrogen elementP There is also a cardoxyl group and
an R group which doth help with the stadilising the structureP The three-dimensional shape
of the enzyme is supported dy these amino acid side chainsP The amino acid side chains also
tend to create an actie site due to the r group which is the iariadle group that always
changes and creates iariety in the enzymesP The amino acid side chains hold the specifc
tertary structure together and they also hold the hydrogen donds detween the polypeptde
chainsP
Lock ane Key moeel:
In the early scientfc studies, the scientst haie come up with the ‘lock and key model’
which represented the idea of how enzymes and sudstrate came together to form a product
(enzyme-sudstrate complex)P The lock and key model is the idea that the sudstrate and the
enzyme ft into each other the same way a lock and key would doP oweier, soon the
scientsts realised that the lock and key model didn’t fully portrait the actual way of how the
enzymes and the sudstrate dind to each otherP There has deen eiidence that when the