Enzymes Flashcards
What are enzymes?
They are globular proteins with a specific tertiary shape and are usually specific to one reaction.
what is the Primary structure of proteins
Order of amino acids
what is the Secondary structure of proteins
The way an amino acid folds or coils into an alpha helix or a beta pleated sheet
what is the Tertiary structure of proteins
They way it folds the protein to its final shape.
What are proteins made up of
Amino acids
What is the role of an enzyme
Is to catalyse reactions by interacting with a substrate
How do enzymes speed up the rate of reaction
Enzymes lower the activation energy meaning less energy is required to start
What is activation energy
The minimum quantity of energy needed to undergo a reaction
What are anabolic reactions
The reaction required for growth (building up). The substrate molecules are held closely together in the active site, reducing any repulsion between molecules so the reaction happens faster.
What are catabolic reactions
A break down reaction releasing energy (bonds are broken). Strain is put on the bonds in the substrate by the active site. The strain means bonds are weakened and substrate molecules break up easier.
What is metabolism
The sum of the different reactions and reaction pathways happening in a cell or organism as a result of the control of enzymes.
Lock and key hypothesis
Enzymes are exactly complementary to the shape of the substrate
When they collide they form an enzyme substrate complex and catalyse the reaction forming an enzyme product complex
Induced fit hypothesis
Active sites are not exactly complementary but change shape to a specific substrate to become complimentary.
They collide, form an enzyme substrate complex and catalyse forming an enzyme product complex
Extracellular enzymes
Enzymes that work outside the cell that made them. E.g. Trypsin is secreted in the pancreas but functions in the Small intestines.
Intracellular enzymes
Enzymes that act within the cell the cell that produces it. An example would be catalase which breaks down hydrogen peroxide.
Factors that affect the rate of reaction
Temperature - more KE, optimum temp
pH - optimum ph
Enzyme concentration - more enzymes the faster the reaction however it is limited by substrate concentration
Substrate concentration - more substrate molecules more collisions with active site, faster rate of reaction, limited by enzyme concentration
What is vmax
The maximum rate of reaction, as a active sites are occupied and no enzyme substrate complexes can be formed
What are enzyme inhibitors
Are molecule that prevent enzymes from catalysing reactions, or slows them down. This ensures there is no over production of products.
Competitive inhibitor
Has a similar shape to the active site and can bind to it. This blocks the active site and the enzyme cannot carry out its function.
Non competitive inhibitor
Has a different shape to the substrate and cannot bind to the active site. Instead it binds to the ALLOSTERIC site. This changes the active site by causing the tertiary structure to change shape.
End product inhibition
The end product inhibits an enzyme earlier on in the process. This means the process controls itself.
Reversible inhibition
Have weak hydrogen bond or ionic that can be broken
Irreversible inhibition
Have string covalent bonds that cannot be broken.
Inorganic cofactors
Are inorganic molecules or ions that help the enzyme and substrate to bind together. They are obtained by via the diet as minerals.
