Question

enzyme shape
enzymes are complex proteins with a structure that consists of folds and pockets. the shape of the active site on an enzyme determines what substrates it can catalyze. by binding with the enzyme at the active site, a substrate can quickly be converted into products.

figure 3: active site of an enzyme.

an enzyme works best at optimal ph and temperature. enzymes are sensitive to fluctuations in these conditions. if an enzyme is placed in less - than - optimal conditions, the reaction rate will slow down. this is because ph and temperature can affect an active sites shape. if the active site changes shape, it can no longer efficiently catalyze reactions.

in figure 4 below, you can see that as the ph changes, the rate of reaction also changes. at phs too low or too high, the enzyme becomes denatured, or unable to catalyze a reaction.

figure 4: the reaction rate of an enzyme is highest at an optimum ph and lowest when it becomes denatured.

1. identify the optimum ph for the reaction rate of the enzyme pictured in figure 4. mark the optimum on the graph with a star.

1. infer from figure 4 whether enzymes work over a large or small range of phs and temperatures.

1. explain how increasing the concentration of an enzyme would affect the reaction rate.

Explanation:

5.

Step1: Locate peak of graph

The peak of the reaction - rate vs pH graph represents the optimum pH.

Step2: Identify x - value at peak

The x - value (pH) at the peak of the graph in Figure 4 is 3. Mark this point on the graph with a star.

Examine the range of pH values over which the reaction rate is non - negligible. The graph in Figure 4 shows that the reaction rate is significant only over a narrow range of pH values (from approximately 2 to 4). Similarly, enzymes are also sensitive to temperature and typically work over a small range of temperatures as well.

In the presence of sufficient substrate, increasing the enzyme concentration will increase the number of available active sites. More substrate molecules can bind to the active sites simultaneously, leading to an increase in the reaction rate until all substrate is used up or some other limiting factor is reached.

Answer:

The optimum pH is 3. Mark the point on the graph where pH = 3 with a star.

6.