Factors Affecting Enzymes. Flashcards
How does temperature affect enzyme-controlled reactions?
• At higher temperatures, the enzyme and substrate molecules move faster and collide more often.
• In general, the higher the temperature, the faster the reaction.
• If the temperature becomes too high, the amino acid chains in the protein start to unravel, changing the shape of the active site.
• The enzyme is now denatured.
• The substrate can no longer bind and so the rate of reaction decreases.
• Once all the enzyme molecules are denatured the reaction stops.
• Most denatured enzymes cannot return to their original shape - the change is irreversible.
How does pH affect enzyme-controlled reactions?
• Each enzyme has its optimum pH.
• A change in pH affects the interactions between amino acids in a chain. This may make the enzyme unfold, changing the shape of the active site.
• The enzyme will then be denatured.
How does substrate concentration affect enzyme-controlled reactions?
• In general, the higher the substrate concentration is, the faster the rate of reaction.
• But at a certain substrate concentration, all the enzyme molecules are bound to substrate molecules.
• The rate of the reaction will be at its maximum.
• Any further increase in the number of substrate molecules will not increase the rate of reaction as there are no enzymes for them to bind to.
What factors affect enzymes?
The rate of an enzyme-catalysed reaction depends on a number of factors including temperature and pH. It is also affected by the concentrations of the enzyme and substrate. The conditions in which an enzyme works best are the optimum conditions.
