Unknown Labs

Session Objectives:

By the end of this laboratory session, the student shall be able to:

• Describe the colony and microscopic morphologies of various unknown microorganisms
• Perform available biochemical tests on various unknown microorganisms
• Determine the identity of an unknown microorganism using appropriate algorithms presented in class
• Perform and/or assure that all appropriate QC was conducted on the used biochemistry kits and recorded in the QC workbook.
• Follow all safety precautions that should be observed when working with the chemical and biological substances used in this laboratory experience

Virtual Lab Instructions

• Go to http://vlab.amrita.edu/?sub=3&brch=76&sim=1109&cnt=1
• Complete the virtual lab and fill in the chart below to the best of your abilities.
• Answer the following questions:

1. Explain the principle behind catalase and coagulase test?

• You are provided with a mixed culture of organism. Provide a flow chart to show different procedure involved in the identification process.

• Explain a rapid biochemical test for the identification of Staphylococcus aureus?

• Explain the principle of nitrate reduction test?

• While performing the gram stain technique, you noticed that the culture contains gram negative rods and gram negative cocci. Explain in detail about your further proceedings of the experiment?

• Explain the following:

1. Alpha hemolysis
   1. Beta hemolysis
   1. Gamma hemolysis

• A bacterium grown in the starch agar plate is suspected to have the enzyme amylase. How will you confirm the presence of amylase in the medium?

• Explain the different biochemical tests of bacteria that rely on the fermentation of carbohydrates?

• Escherichia coli has the ability to grow on the EMB agar plate, but Staphylococcus aureus cannot. Explain the reason?