Question

1) Based on the explanation on the interaction between starch, salivary amylase and iodine solution at the beginning of the presentation, please give a brief explanation on the differences in colour over time for each concentration.

2) Why do you think the rate of reaction increases as the concentration of the enzyme is increased? Is the rate of reaction increasing indefinitely as the concentration increases?

3) Why do you think the reaction rate is different as the pH of the reaction mix changes. Please provide brief explanation.

4) What do you think happens to a polypeptide chain of the enzyme when the hydrogen ion concentration (i.e. pH) is altered?

Answer 1

1) When Iodine interacts with starch a complex of blue to black is observed, but there is no reaction with glucose. On reaction with glucose red or yellow color is viewed which is the color of the iodine. Enzyme amylase begins to work faster, as the blue color of the starch gets vanished. The blue color will retained when the enzyme amylase is suspended and there is no way for the hydrolyzation of starch.

Benedict's reagant plays an eminent role for testing the existence of glucose in the samples. Benedict's reagant is in blue color and it will change to green when it is added to glucose solution with lower concentration. Reddish orange is observe at higher concentration. There is no reaction between starch and Benedict's reagant, the blue color is retained.

2) When the concentration of the enzyme increases, rate of the reaction increases. Enzymes has a greater ability to increase the reaction rate, the reason is collision between substrate molecules and the enzyme molecules takes place leads to the formation of more products.

Rate of the reaction will not increase indefinitely, because at a particular point of time the enzymes becomes saturated. Due to this enzyme saturation the substrate is not able to suit for collision, still there is availability of more substrates.

3) As the pH of the reaction mix changes will make a difference in the reaction rate, because when the pH is less the rate of the reaction will be high due to the presence of more H+ ions. The chance of collision of reactants is high.

4) By altering the Hydrogen ion concentration will affect the product formation rate, this is due to the change in the enzyme shape. The active site gets altered and minimise the interaction capability with the substrate.