Worksheet
NOTE: As you read the information in the Microbiology Handbook, there may be some terms you are not familiar with – such as 16s ribosomal RNA and Polymerase Chain Reaction. Refer to your text to read background material explaining any terms or processes with which you are not familiar.
Record the results of your investigations of each unknown in Table 1 by completing the following steps: 1) Apply the stain to your first unknown slide and examine it under the microscope. 2) Record the shape of the bacteria, the arrangement of the bacteria, and the gram staining characteristics. 3) Analyze and record the G+C content of the sample by dragging the DNA tube that corresponds to the bacterial sample to the GC Content Measuring Apparatus. (Note: the identification of the DNA tubes may be confusing; the red tube belongs to sample #1, the blue tube belongs to sample #2, and the green tube belongs to sample #3) 4) Compare the slide to the pictures in the Microbiology Handbook, and record the name of the species you believe it to be. 5) Repeat these steps for sample #2 and sample #3. 6) Click reset to obtain 3 new bacterial samples to test, and repeat steps 1-5. 7) Continue to reset the slides and continue testing until you have identified each bacterial species described in the Microbiology handbook, as well as one unknown species.
Table 1:
Shape Arrangement Gram + or Gram - GC Content Species
Bacilli Irregular rods Neg ~51% E. coli
Cocci Irregular clusters Pos. ~25% Staph Aureus
Cocci Chains Pos. ~30% Strep mutans
No match No match ~50% E. coli
Cocci Pairs Neg. ~75% Veilonella sp.
Cocci Cubical packages of 4-8 cells Pos. ~45% Sarcina sp.
Bacilli Curved rods with flagellum Neg. ~35% Vibrio Cholerae
Oval Cocci/bacilli Oval irregular Neg ~67% Bordetella pertussis
Answer the following questions:
1. Which of the species