Question

1a) what is the relationship between substrate concentration and reaction rate?

b) Describe how the enzyme structure is effected:

1. i) below the optimal temperature

ii)above the optimal temperature?  

c)Why is enzyme activity reduced at pH values above or below the optimum? How does the enzyme structure change at non-optimum pH?

Answer 1

Ans:-1)

A) For an enzyme catalysed reaction there is a hyperbolic curve between reaction rate and concentration of substrate.

Increasing substrate concentration will also increase the rate of reaction to a certain point. Once all the enxymes have bound, any substrate increase will have no effect on the rate of reaction because all the available enzyme will get saturated.

B) Every enzyme has an optimum temperature, the temperature at which the enzyme activity is greatest.

I) Below the optimal temperature :- The structure remain same.

Enzymes are mainly inactive below the optimal temperature. Because at low temperature, the number of successsive collision between enzyme and substrate is reduced as their molecular movement is decreased.

II) above optimal temperature :-As the temperature increased, more Enzyme molecules active site 's shape will be less complementary to the shape of their substrate and more enzymes will be denatured. This will decrease the rate of reaction.

C) The pH value at which enzyme is most active is called optimal pH value.

When pH value of reaction medium changes(either increase or decrease from optimal pH) , the shape and structure of enzyme reaction will change. Due to it activity of enzyme slows down and then stops. The of active site changes with change in pH.