Questions on Microbial Growth Curve

944 WordsJan 7, 20184 Pages
Q1. Discuss the four phases of the bacterial growth curve. The first phase of bacterial growth is known as the 'lag phase.' The 'lag phase' is when the population is "temporarily unchanged" (Todar, 2012, Growth: 3). However, the phrase 'lag phase' may be something of a misnomer. "Although there is no apparent cell division occurring, the cells may be growing in volume or mass, synthesizing enzymes, proteins, RNA, etc., and increasing in metabolic activity" (Todar, 2012, Growth: 3). The environment is apparently dormant, but the conditions for growth are bubbling beneath the surface. The second phase of the bacterial growth curve is known as the exponential or log phase and features the most dynamic growth. "The exponential phase of growth is a pattern of balanced growth wherein all the cells are dividing regularly by binary fission, and are growing by geometric progression" (Todar, 2012, Growth: 3). During this phase, the bacteria are multiplying rapidly, as much as can be accommodated by the environs in which they are located. However, the exponential phase of rapid expansion cannot continue indefinitely. The third phase is the stationary phase, whereby "population growth is limited by one of three factors: 1. exhaustion of available nutrients; 2. accumulation of inhibitory metabolites or end products; 3. exhaustion of space, in this case called a lack of biological space" (Todar, 2012, Growth: 3). The bacteria are now in a new state of homeostasis with their

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