Enzyme action 2.1.4 (a,b,c) Flashcards
what are enzymes?
biological catalysts
what are the properties of enzymes?
globular proteins with a specific 3D shape
what do enzymes do?
lower the activation energy needed for a substrate to react
allows substrates to react at a faster rate
what are anabolic reactions?
reactions which are required for growth
catalysed by enzymes
what are catabolic reactions?
reactions which are required for breaking down
catalysed by enzymes
what effects enzyme activity?
temperature
pH
pressure
what is the Vmax?
the maximum rate of an enzyme-controlled reaction
how does a reaction work?
molecules collide with each other at the right energy level for it to be a successful collision
what is the activation energy?
the energy required for a reaction to start
why do enzymes lower the activation energy?
they bind to reacting molecules to help them collide successfully
what are the two hypotheses for enzyme action?
lock and key hypothesis
induced-fit hypothesis
outline the lock and key hypothesis
the tertiary structure of an enzyme produces a shape which is complimentary to a specific substrate molecule - called the active site
the specific substrate binds to the active site to form an enzyme-substrate complex
the substrates then react and the products formed form an enzyme-product complex
the products leave and the enzyme is able to take another substrate
what is the active site?
area of a protein which has a shape similar to the substrate
outline the induced-fit hypothesis
the active site of an enzyme changes shape when it interacts with a substrate
the interactions lead to a change in the enzyme’s tertiary structure which increases the binding and puts further strain on the substrate
this leads to the bonds being weakened and thus lowering the activation energy
what are the two types of enzyme?
intracellular
extracellular
what are intracellular enzymes?
enzymes which work within a cell
example of intracellular enzymes?
catalase
what does catalase do?
breaks down hydrogen peroxide into oxygen and water
prevents it’s toxic accumulation
what are extracellular enzymes?
enzymes which work outside of a cell
why are extracellular enzymes important?
large polymers need to be broken down into smaller groups before they can enter a cell
examples of extracellular enzymes?
amylase
trypsin
both used in digestion
what is trypsin?
it is a protease which breaks down proteins into smaller peptides which are later broken down into amino acid
where is trypsin released from?
the pancreas
how is starch digested?
amylase breaks starch into maltose
maltase breaks maltose into glucose which is then absorbed into the blood stream
