Nature has engineered the structures of control enzymes so that their activities - (Sep/01/2013 )

Nature has engineered the structures of control enzymes so that their activities may be modulated rapidly by small changes in the concentrations of certain key effector molecules.

Discuss this statement with reference to phosphofructokinase

I need help with this question from a past paper. Just need help with how to address this question. 
Thankyou

lmgtfy