The effect of temperature on the activity of the enzyme lactase in breaking down lactose can be explained by understanding the relationship between enzyme activity and temperature. Enzymes are proteins that act as biological catalysts, speeding up chemical reactions in living organisms. They have an optimal temperature at which they function most efficiently.As the temperature increases, the kinetic energy of the enzyme and substrate molecules also increases, leading to more frequent collisions between them. This results in an increased rate of enzyme-substrate complex formation and a higher rate of lactose breakdown. However, this is true only up to a certain temperature, which is the optimal temperature for lactase activity.The optimal temperature for lactase activity is typically around 37C 98.6F , which is the normal human body temperature. At this temperature, the enzyme works at its maximum efficiency, breaking down lactose at the highest possible rate.If the temperature continues to increase beyond the optimal temperature, the enzyme's activity will start to decline. This is because high temperatures can cause the enzyme's structure to become unstable and denature. Denaturation is a process in which the enzyme loses its specific three-dimensional structure, which is crucial for its function. A denatured enzyme can no longer bind to its substrate effectively, resulting in a decrease in the rate of lactose breakdown.Conversely, if the temperature is too low, the enzyme's activity will also be reduced. Lower temperatures result in decreased molecular movement and fewer collisions between the enzyme and substrate, leading to a slower rate of enzyme-substrate complex formation and lactose breakdown.In summary, the effect of temperature on the activity of the enzyme lactase in breaking down lactose follows a bell-shaped curve. The enzyme's activity increases with temperature up to its optimal temperature around 37C , after which it declines due to denaturation. At temperatures below the optimal temperature, the enzyme's activity is reduced due to decreased molecular movement and fewer collisions between the enzyme and substrate.