1. The answer is "<span>the energy required to start the reaction".
</span>This energy is called as activation energy of the reaction. If the activation
energy is high, reaction is slow. Enzymes help to carry out the reaction by
a new path by reducing the activation energy. But the energy of reactants
and the products remain as same as without enzyme.
2. The answer is "reaction in cells would be too slow to sustain life<span>".
</span>If the activation energy is very high for the reaction, then that reaction will
be very slow and will require more time<span> to complete the reaction. Then survival is
very low. Hence, the roll of enzymes is very important to sustain life.</span>
