Question

Animal bodies (and even plant bodies for that matter) are complex enough that life couldn't exist without enzymes. Enzymes are usually large, complex biological catalysts that are expensive to make. Enzymes speed up the rate of chemical reactions without being used up during the reaction (they can be reused many times). They are highly specific in the reactions they regulate. Knowing what enzymes are and how they function, WHY does this help explain why complex lifeforms could not exist if there were no enzymes

Answer 1

Enzymes need specific conditions to work at their maximum levels, i.e. they need specific pH, temperature, etc. The enzyme activity increases with the increase in temperature because it increases the kinetic energy of the molecules. This make the reactants to collide more with each other to overcome the energy barrier by means of activation energy. Activation energy is needed for the molecules to react.

Enzymes catalyse many of the biochemical reactions starting from the replication of DNA and degradation of dead cells. In the absence of enzymes, cells cannot carry out the functions necessary to maintain the cell structure and provide energy. Thus, complex life forms cannot exist in the absence of enzymes.