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In the curve above, e. coli is grown in 500ml of nutrient broth (nb). To save funds, the instructor wants to make two changes. Switch the lab media from nb to tryptic soy broth (tsb) but keep the stock bacterium in nb. Cut the volume of media from 500ml down to 250ml. You know that these changes will affect the growth curve she has given. Hypothesize what changes will occur to the growth curve above when you make these two changes. Make sure to explain why those changes will occur.

User Nikosd
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Final answer:

The switch to TSB and a reduction in media volume could affect the E. coli growth curve by altering the lag, exponential, stationary, and death phases, due to differences in nutrition and waste accumulation.

Step-by-step explanation:

When switching from Nutrient Broth (NB) to Tryptic Soy Broth (TSB) and reducing the culture volume from 500ml to 250ml, we can hypothesize potential changes to the growth curve of E. coli. TSB is a general all-purpose medium that supports the growth of a wide variety of organisms and may provide different nutrients or growth conditions compared to NB. This could influence the growth curve in several ways. The lag phase could be shorter or longer depending on how quickly E.coli can adapt to the new medium. The exponential growth phase might also be altered, potentially seeing a change in the growth rate if TSB better suits the bacteria's nutritional requirements. The stationary phase may occur at a different cell density due to the smaller volume, as a greater cell density may be reached more quickly in 250ml than in 500ml, potentially leading to an earlier onset of resource limitation.

Additionally, switching to a smaller volume could lead to quicker accumulation of waste products and depletion of nutrients, which might precipitate the death phase earlier. The overall carrying capacity may be reduced due to the smaller volume, even though this does not impact the slope of the exponential growth phase directly, it determines the cell density at which the culture enters the stationary phase.

User Chand Priyankara
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