Part Labeling 16pts total) Figure 3 -Bacterial Growth Curve Incubated at 30%C 14
ID: 91494 • Letter: P
Question
Part Labeling 16pts total) Figure 3 -Bacterial Growth Curve Incubated at 30%C 14. A growth curve was constructed over a 24hour period for the facultative anaerobeCitrobacter freundii (Figure 3), the culture was incubated at 30°C in minimal salts broth, aerobically, Even though the growth curve was made using the conditions listed above, Citrobacter freundli actually has an optimal growth temperature of 37°C and can metabolize both glucose and lactose. Indicate how each growth curve would change under the conditions indicated in the figure title of each individual graph in figure 4, Draw the new curve directly onto the reference curve given in figure 4 to indicate how it would change, ifthere would be no change then write "no change (ipt/graph) Figure 4- Incubated at 17"C Incubated at 20 C Double Iglucoselinmedium 5 Naaadded to mediumExplanation / Answer
14) In the first case, when the bacterial culture of Citrobacter freundii incubated at 200c , it requires much time to adapt with new environmental conditions especially with temperature. This phase of growth is called Lag phase. Here there will not be any multiplication or division of cells.
In the second case, when the bacterial culture incubated at 370C, it requires little time to adapt with the new environmental cindition because the temperature applied here is the optimal temperature. This phase is called log phase. Here the cells get multiplied or divided at naximum rate.
In the third case, the glucose quantity in the medium is doubled. As the given bacteria is a glucose fermentor, this condition makes them to survive and multiply faster by utilizing glucose nutrient available in the medium. Here also it will take little time to adapt the new condition.
In the fourth case, the medium is supplemented with 5% Nacl. The Nacl is a growth inhibitor of Citrobacter freundii. It will inhibit the bacterial culture resulting in no multiplication or division of cells. Due to lack of nutrients available in the media and due to action of growth inhibitor Nacl, some cells starts to die. Here the growth phase is stationary at the beginning followed by death phase.