The effect of pH on the rate of an enzyme-catalysed reaction for three different enzymes (each with a different optimum pH)
Iodine can be used qualitatively to indicate the presence or absence of starch from a sample
Investigating the effect of pH on enzyme activity
Temperature can both affect the speed at which molecules are moving (and therefore the number of collisions between enzyme and substrate in a given time) and can denature enzymes (at high temperatures). pH, however, does not affect collision rate but only disrupts the ability of the substrate to bind with the enzyme, reducing the number of successful collisions until eventually, the active site changes shape so much that no more successful collisions can occur.