C1.1 Flashcards
Enzymes and metabolism
What are enzymes?
proteins that function as biological catalysts
What are catalysts?
a substance that speeds up the rate of a chemical reaction. They are effective in small amounts and remain unchanged at the end of the reaction
How are enzymes classfied?
according to the reaction they catalyse
What is anabolism?
the synthesis of complex molecules from simpler molecules including the formation of macromolecules from monomers by condensation reactions
What is catabolism?
the breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers
what is the substrate?
the starting substance or reactant in a reaction catalyzed by an enzyme. It is the molecule which the enzyme reacts with
What is the product?
what the substrate is converted to after the reaction catalysed by the enzyme
What is the active site?
region of an enzyme molecule where the substrate molecule hinds and catalysis occurs
What is the enzyme-substrate complex?
the temporary structure formed when a substrate binds to the active site of the enzyme
What is the induced-fit model?
the binding of the substrate to the enzyme causes a change in the shape of the enzyme and the substrate resulting the proper alignment of the catalytic groups on its surface which enable catalysis to take place
What is the Lock and key model?
when the active site of the enzyme is the complementary shape of the substrate and so fits to the substrate precisely.
What type of reactions does an enzyme catalyse?
each enzyme catalyses either a single chemical reaction or a group of closely related reactions.
How do the substrate and active site come together?
through collisions between the two thats caused by kinetic energy in both of them.
What is an immobilized enzyme?
an enzyme attached to an inert, insoluble material, enabling recovery, reuse and improved enzyme stability
What are the advantages of using an immobilized enzyme in an industrial process?
it permits the reuse of the enzyme preparation
the product is enzyme free
the enzyme may be much more stable and long lasting, due to protection by the inert matrix
What is the EIM system?
the enzyme immobilized on or in a membrane is a widely used method in food processing or pharmaceuticals
What type of protein is an enzyme?
Globular
What is Denaturation?
denaturation occurs when weak intermolecular interactions within the globular protein break, changing the 3 dimensional shape of the active site.
What is the impact of denaturation?
since the shape of the active site has changed, the enzyme and substrate can no longer bind together.
What is the effect of temperature on enzymes?
proteins are denatured by heat, hence the rate of denaturation increases at temperatures higher than the optimum so at the temperature rises the amount of enzyme activity progressively decreases and the rate of reaction is slowed.
What is catalase?
the enzyme which catalyzes the breakdown pf hydrogen peroxide
What are the effects of PH on enzymes?
a change in ph alters the bonding patterns, progressively changing the 3d shape of the molecule rendering the active site inactive, however unlike temperature this may be reversed if the change in PH is not too extreme
What is activation energy?
the small amount of energy needed to initially weaken or break down the bond of the substrate
What are extracellular enzymes?
an enzyme secreted by the cell through endocytosis that carries out functions outside the cell
