Biology - Enzymes

HideShow resource information
  • Created by: Dariaxx
  • Created on: 17-10-16 11:40
View mindmap
  • Biological molecules - Enzymes
    • Globular proteins that act as catalysts
      • catalysts alter the rate of a chemical reaction without undergoing permanent change
    • Enzymes as catalysts lower activation energy
      • there is an activation energy, like an energy hill or barrier, which must initially be overcome before reaction proceeds
      • enzymes work by lowering the activation energy level.
        • In this way enzymes allow reaction to take place at a low temperature than normal
          • This enables some metabolic processes to occur rapidly at the human body temperature
            • without enzymes these reactions would proceed too slowly to sustain life as we know it
    • Factors Effecting Enzyme Action
      • Temperature
        • A rise in temperature increases the kinetic energy of molecules
          • As a result, the molecules move around more rapidly and collide with each other more often
            • In an enzyme-catalysed reaction, this means that the enzyme and substrate molecules come together more often in a given time
              • If the temperature keeps keeps increasing it causes the hydrogen and other bonds to break. Also changes the shape of the active stite
      • pH
        • A change in the pH alters the charges on the amino acids that make up the active site
          • As a result, the substrate can no longer become attached to the active site
        • depending on how significant the change of pH is it may cause bonds maintaining the enzyme tertiary structure to break
      • Enzyme concentration
        • An increase in the amount of enzyme leads to a proportionate increase in the rate of reaction
          • There is more substrate than the enzymes active sites can cope with
      • Substrate concentration
        • If the concentration of enzyme is fixed and substrate concentration slowly increased, the rate of reaction increases in proportion to the concentration of substrate
          • at low substrate concentration, the enzyme are not working at their full capacity
      • enzyme inhibition
        • competitive inhibitors
          • which bind to the active site of the enzyme
            • prevents substrate from temporarily binding
        • non-competitive inhibitors
          • which bind to the enzyme at a position other than the active site
            • changes the shape of the active site
    • measuring rate of change
      • we can measure change inthe rate of a reaction at any point on the curve of a graph
        • we do this by measuring the gradient at our chosen point
    • measuring enzyme-catalysed reactions
      • the formation of the products of the reaction, for example the volume of oxygen produced when the enzyme catalase acts on hydrogen peroxide
      • the disappearance of the substrate, for example the reduction in concentration of starch when it is acted upon by amylase


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Biological molecules resources »