Bacterial Growth Lab
Title: Chapter 7: Bacterial Growth
Purpose: The purpose of this experiment is to observe the bacterial growth of Escherichia coli under various conditions. Physical factors and nutritional requirements determine the overall concentration of the bacteria. Along with the use of a spectrophotometer and the technique of serial dilution, countable colonies can be obtained. Results are plotted on a semi-log graph in order to observe the different growth curves corresponding to optical density (cell density) vs. time.
Materials and Procedure:
The materials that were used were micropipettes, Eppendorf tubes, one LB tube, 3 LB plates, E. Coli, spectrometer, and a cuvette.
Procedure:
1- Transfer 1 ml culture medium of Luria Broth …show more content…
Procedure A, examined the relationship toward the physical factors (such as, temperature). The use of the spectrophotometer provides optical density readings (OD) which can be translated to concentration (cells/mL) due to the relationship of: 1 OD=1.0 x 108 cells/mL. “The OD is directly proportional to the number of cells, meaning the higher the OD, the more cells in the medium” (Scheurle, p. 43). Acknowledging this fact, serial dilution technique can be applied to obtain a countable number of colonies on a petri plate by diluting the solution over and over again; hence the word …show more content…
coli. Luria Broth Agar (LB) is rich medium, as noted previously “provides all nutritional components needed by the bacterial cell to grow. The exact chemical constitution of this medium is not known” (Scheurle, p.41-42). Glucose Minimal Salt Agar (GMS) is minimal medium “provides only the essential nutrients and forces the cell to synthesize all of its metabolites. The exact chemical composition is known and defined” (Scheurle, p.42). E. coli are prototrophs; “cells that are equipped with all the enzymes needed to synthesize all the cellular building blocks” (Scheurle, p. 42) were grown on these two plates to visualize how nutritional factors take part in bacterial growth. According to the results (per group), the E. coli culture in the LB plate were in greater numbers than the GMS plate, which is in good agreement with the expected; “cell growth of prototrophs is always faster in rich medium than in minimal medium” (Scheurle, p.42). The E. coli culture in the GMS plate have to “work” extra hard in building their core metabolites. Potentially, cell growth is obtained for GMS media; however, the lag time is longer, due to adjustment reasons, as well as a shorter log phase, because conditions are not optimal for high numbers in cell
Purpose: The purpose of this experiment is to observe the bacterial growth of Escherichia coli under various conditions. Physical factors and nutritional requirements determine the overall concentration of the bacteria. Along with the use of a spectrophotometer and the technique of serial dilution, countable colonies can be obtained. Results are plotted on a semi-log graph in order to observe the different growth curves corresponding to optical density (cell density) vs. time.
Materials and Procedure:
The materials that were used were micropipettes, Eppendorf tubes, one LB tube, 3 LB plates, E. Coli, spectrometer, and a cuvette.
Procedure:
1- Transfer 1 ml culture medium of Luria Broth …show more content…
Procedure A, examined the relationship toward the physical factors (such as, temperature). The use of the spectrophotometer provides optical density readings (OD) which can be translated to concentration (cells/mL) due to the relationship of: 1 OD=1.0 x 108 cells/mL. “The OD is directly proportional to the number of cells, meaning the higher the OD, the more cells in the medium” (Scheurle, p. 43). Acknowledging this fact, serial dilution technique can be applied to obtain a countable number of colonies on a petri plate by diluting the solution over and over again; hence the word …show more content…
coli. Luria Broth Agar (LB) is rich medium, as noted previously “provides all nutritional components needed by the bacterial cell to grow. The exact chemical constitution of this medium is not known” (Scheurle, p.41-42). Glucose Minimal Salt Agar (GMS) is minimal medium “provides only the essential nutrients and forces the cell to synthesize all of its metabolites. The exact chemical composition is known and defined” (Scheurle, p.42). E. coli are prototrophs; “cells that are equipped with all the enzymes needed to synthesize all the cellular building blocks” (Scheurle, p. 42) were grown on these two plates to visualize how nutritional factors take part in bacterial growth. According to the results (per group), the E. coli culture in the LB plate were in greater numbers than the GMS plate, which is in good agreement with the expected; “cell growth of prototrophs is always faster in rich medium than in minimal medium” (Scheurle, p.42). The E. coli culture in the GMS plate have to “work” extra hard in building their core metabolites. Potentially, cell growth is obtained for GMS media; however, the lag time is longer, due to adjustment reasons, as well as a shorter log phase, because conditions are not optimal for high numbers in cell