Why do bacteria probably have the most growth in the incubator, biochemically reasoning?

Answer 1

The actual reason is that the incubator provides exactly the right temperature for bacterial growth. All enzymes have an optimal temperature where they perform the best. Human enzymes work best at 37.6 degrees C, which is not surprisingly body temp. It also comes as no surprise that bacteria that live in the human body also have enzymes that work best at 37.6 degrees C. Thus, if you grow two cultures of E. coli, one at 25C and the other at 37 C the one at higher temps will do significantly better, because it's enzymes are working much more efficiently.

It really doesn't have much to do with molecules moving faster. the differnence between molecule movement at 37C and room temp isn't very great. CO2 incubators are critical if the bacteria is anaerobic, but most bacteria used in labs aren't.

Answer 2

In biochemical terms, the higher temps speed up reactions. Molecules bump into each other more frequently, so the right chance collisions happen more often and the various things a bacteria need to do to live and replicate happen faster.

The use of 37C specifically is just a result of our bias towards studying human pathogens.

Answer 3

The answer to this question lies in the differences between an incubator and the outside. Most incubators are stable body temp and have an enriched CO2 atmosphere.

That data should be enough information to look in your text for the answer. :)