The effect of pH on the rate of an enzyme reaction: data analysis | Exit Quiz | Oak National Academy

Which statement defines the term ‘rate of reaction’?

• How much substrate is converted into product.

• How long a chemical reaction takes.

• How fast a chemical reaction occurs.

• How much enzyme is used.

Answer explanation

The faster a reaction takes place the higher the rate of the reaction is.

Calculate the missing rate of reaction.

Answer explanation

Rate = 1 ÷ 5 Rate = 0.2

On which axis would you plot the rate of a reaction, when it is plotted against pH?

• x-axis

• y-axis

Answer explanation

pH would be plotted on the x-axis because it is the independent variable and the rate of reaction would be on the y-axis.

In the graph below which letter shows when an enzyme is at its optimum temperature?

• a

• b

• c

Answer explanation

At point b the rate of reaction is the highest and the enzyme is at its optimum temperature.

When enzyme reaction rate is at its highest all the ___ sites are full.

Answer explanation

The shape of the active site and the substrate are complimentary. When all the active sites are full, the enzyme is working optimally and the rate of reaction is at its highest.

What word describes an enzyme whose active site has changed shape due to being placed in unfavourable conditions?

Answer explanation

Different enzymes have different optimal conditions. Outside of these the active site can change and the substrate and enzyme can no longer bond together to catalyse a chemical reaction.