Problem:

Usually the protocol for preparing electro competent E. coli cells calls for growing the cells at 37deg and 225rpms until they reach OD of 0.3.

Required:

Question 1: Is there any reason they should grow at optimal conditions for growth, instead of at suboptimal, for example at 30 degrees?

Question 2: What is the physiological/epigenetic difference between a culture of OD 0.2 vs 03. vs 0.3?
Show your work.