Why must living things rely on thousands of catalysts for chemical reactions necessary for life?

Answer 1

Well, you don't need enzymes (biological catalysts) if you're willing to wait a century or two to digest a burger. Without catalysts, complex reactions like digestion would take too long and the organism could not extract energy from the nutrients it eats in a practical time frame. In addition, speed is everything in the biological world. Some reactions and their speed relative to other organisms reactions determines who survives and who doesn't, among other aspects of life. If a plant is slow to photosynthesize and grow in a habitat high in competition for sunlight real estate, other autotrophs will surely take over.

Answer 2

First of all living organisms use catalysts (more specially - enzymes), because without them it'll be needed extremely long period of time for all of the biochemical reactions to finish.Of course, catalysts are not the only thing which may change the speed of the reaction - if the environmental conditions (temperature, pH, pressure and others) are changed the reactions also may start to run faster.But the change of this conditions may kill the organisms or reduce their fitness.For instance, if the temperature becomes higher - yes the reactions would start to run faster.But the nucleic acids and the proteins of the organism are going to denaturate (their folding is going to be damaged), so this eventually would kill or damage the organism (that's what happens when a living tissue is burnt).

There are so many biological catalysts simply because every reaction is very specific.Different kinds of changes occur with the substrate/s so different catalysts would be needed to ''help'' in the realizing of these changes.There is no universal catalyst.If someone finds it he'll become a millionaire (or even more) but this just can't happen because of the above reasons.

Answer 3

Because in the absence of these biochemical catalysts (enzymes) the reactions would be impossible or too slow.