Lab Report
LAB REPORT NUMBER TWO
DATE: 3/25/2010
inal attachment Lab Experiment number 11
PURPOSE:
To learn the Gram stain technique, the reason for the stain, and how to identify the results of the organisms stained.
MATERIALS:
Bunsen burner, inoculating loop, staining tray, glass slides, bibulous paper, lens paper, oil, and microscope
METHODS:
Apply Crystal Violet (Primary stain) for 1 minute.
Rinse with D-water
Apply Iodine (Mordant) for 1 minute.
Rinse with D-water.
Apply Alcohol (Decolorize) for 30 seconds.
Rinse with D-water.
Apply Safarin (Counterstain) for 1 minute.
Blot dry with bibulous paper.
MICROORGANISMS USED:
E. coli, B. cereus, S. aureus & E.coli (mixture)
RESULTS/DATA USED:
E.coli cell shape was bacilli (rod) with a diplobaccillus arrangement. The color was pink because it was Gram negative. B.cereus cell shape was bacilli (rod) with a diplobacillus arrangement. The color was purple because it was Gram positive. S.aureus & E.coli (mixture) cell shape was cocci (spherical) with a staphylococcus arrangement. The color was mostly purple with some noticeable pink but the mixture was Gram positive.
CONCLUSIONS
E. coli is Gram negative, B. cereus is Gram positive, S. aureus & E. coli mixture is Gram positive.
REVIEW QUESTIONS:
Question 1: What are the advantages of differential staining procedures over the simple staining technique?
Answer: Simple stains are used to just give color to microbes on slides. Differential stains tell the chemical composition of organisms.
Source: http://www.bmb.psu.edu/courses/micro107/notes/staining.htm
Question 2: Cite the purpose of each of the following reagents in a differential staining procedure.
Answer:
a. Primary stain: Passes the color of the stain to all of the cells. b. Counterstain: Used to stain red the cells that have been decolorized (Gram – cells). c. Decolorizing agent: removes the primary stain so that the counterstain can be absorbed. d. Mordant: Increases the
DATE: 3/25/2010
inal attachment Lab Experiment number 11
PURPOSE:
To learn the Gram stain technique, the reason for the stain, and how to identify the results of the organisms stained.
MATERIALS:
Bunsen burner, inoculating loop, staining tray, glass slides, bibulous paper, lens paper, oil, and microscope
METHODS:
Apply Crystal Violet (Primary stain) for 1 minute.
Rinse with D-water
Apply Iodine (Mordant) for 1 minute.
Rinse with D-water.
Apply Alcohol (Decolorize) for 30 seconds.
Rinse with D-water.
Apply Safarin (Counterstain) for 1 minute.
Blot dry with bibulous paper.
MICROORGANISMS USED:
E. coli, B. cereus, S. aureus & E.coli (mixture)
RESULTS/DATA USED:
E.coli cell shape was bacilli (rod) with a diplobaccillus arrangement. The color was pink because it was Gram negative. B.cereus cell shape was bacilli (rod) with a diplobacillus arrangement. The color was purple because it was Gram positive. S.aureus & E.coli (mixture) cell shape was cocci (spherical) with a staphylococcus arrangement. The color was mostly purple with some noticeable pink but the mixture was Gram positive.
CONCLUSIONS
E. coli is Gram negative, B. cereus is Gram positive, S. aureus & E. coli mixture is Gram positive.
REVIEW QUESTIONS:
Question 1: What are the advantages of differential staining procedures over the simple staining technique?
Answer: Simple stains are used to just give color to microbes on slides. Differential stains tell the chemical composition of organisms.
Source: http://www.bmb.psu.edu/courses/micro107/notes/staining.htm
Question 2: Cite the purpose of each of the following reagents in a differential staining procedure.
Answer:
a. Primary stain: Passes the color of the stain to all of the cells. b. Counterstain: Used to stain red the cells that have been decolorized (Gram – cells). c. Decolorizing agent: removes the primary stain so that the counterstain can be absorbed. d. Mordant: Increases the