Lock and Key theory GCSE Biology Watch
As the concentration of the substrate increases, so does the rate of enzyme activity. However, the rate of enzyme activity does not increase forever. This is because a point will be reached when the enzymes become saturated and no more substrates can fit at any one time even though there is plenty of substrate available. pH increases so does the rate of enzyme activity. An optimum activity is reached at the enzyme’s optimum pH. A continued increase in pH results in a sharp decrease in activity as the enzyme’s active site changes shape. It is now denatured.As the temperature increases so does the rate of enzyme activity. An optimum activity is reached at the enzyme's optimum temperature. A continued increase in temperature results in a sharp decrease in activity as the enzyme's active site changes shape meaning it has denatured.
i have no idea what the induced fit model is but I highly doubt they'll ask you limitations on models in a bio paper as they only ever spend page on enzymes and if it wasnt on the 2018 or 2019 paper and was done fairly recently before the 9-1 system i highly doubt it'll come in the test. But you should revise it anyway but dont worry about it, but then again i dont know what exam board you're doing. so anyways good luck and soz for the long reply!