Question

The lag phase constitute of _________

(a) No change in number, but an increase in mass

(b) Change in number but decrease in mass

(c) No change in number and decrease in mass

(d) Constant number and mass

I got this question by my college professor while I was bunking the class.

The query is from Cell Growth Kinetics topic in section Homogenous Reactions of Bioprocess Engineering

Answer 1

Right answer is (a) No change in number, but an increase in mass

To explain I would say: The lag phase is the time period when there is no immediate increase in cell number of microorganisms as they are introduced into fresh culture medium. The microorganisms during this phase are trying to acclimatize to the new culture medium as it may be different from the previous one in which the microorganism was growing. Typically cells in the lag period are synthesizing RNA, enzymes, and essential metabolites that might be missing from their new environment (such as growth factors or macromolecules), as well as adjusting to environmental changes such as changes in temperature, pH, or oxygen availability. They can also be undertaking any necessary repair of injured cells.