BIOCHEMICAL CHARACTERIZATION – STUDY HELP There are two parts to this document:

Question

BIOCHEMICAL CHARACTERIZATION – STUDY HELP

There are two parts to this document:

•   PART A: Tu!orial
•   PART B: Questions to prepare for Pre-Lab Quiz & Late Nite Labs quiz

PART A: Tu!orial

•   This website covers most of the tests that you will perform during the Late Nite Labs Biochemical Characterization experiments.

http://www.uwyo.edu/molb2210_lab/info/biochemical_tests.htm#Mannitol

•   For each test, P = positive & N = negative.

PART B: Use the information in this handout and in your Bacterial Characterization lab manual content (on Late Nite Labs) to answer the following questions. It will be helpful to PRINT the lab manual content.

•   If you see a test tube with a column of oxygen bubbles forming, what test is being performed? Describe the reaction that takes place during this test.
•   If you see a purple tube during an oxidase test, what can you conclude about the reaction?
•   How do bacteria metabolize molecules too large to enter the cell?
•   What is indicated by a clearing around bacterial growth in Tributyrin Agar?
•   What color will a specimen turn during an Indole production test if it is positive for Indole production?
•   Why are organisms usually MR or VP positive, but not both?
•   What color will a specimen turn in a citrate test if it is positive for citrase?
•   What is a reaction that can lead to the formation of precipitate in the sulfur reduction test?
•   What color is the precipitate in a sulfur reduction test?
•   How is urease activity detected?
•   What color does a specimen positive for urease turn during the urease test?
•   If a scientist performed the lipase, gelatinase, and mannitol tests on a species of bacteria, the scientist is most likely trying to distinguish between which two species of bacteria?
•   What color will a specimen turn if the species is NOT able to hydrolyze starch?
•   What color will a specimen turn if it tests positive for mannitol?
•   What happens to the constituency of gelatin when metabolized by a gelatinase-positive bacterial species?
•   If a specimen turns red immediately after sulfanilic acid and N, N dimethyl-1-naphthylamine reagents are added in the Nitrate Reduction Test, is the species a nitrate reducer? Yes or No.
•   If a specimen turns red after zinc is added in the Nitrate Reduction Test, is the species a nitrate reducer? Yes or No
•   What species studied during this lab will turn yellow under aerobic (oxidative) conditions and green under anaerobic (fermentation) conditions? You can also refer to the chart on page 4 of this handout to answer this question.
•   Is E. coli IND positive or negative? Is E. coli MR positive or negative?
•   Is E. aerogenes CIT positive or negative? Is E. aerogenes VP positive or negative?
•   If a scientist performed tests on DRINKING WATER, what type of contamination is the scientist most likely researching?
•   Which family of bacteria do the majority of tests in the rapid identification tray identify?

Additional instructions are on the next page.

¬   After you have answered all of the questions in this document, go to the Biochemical Characterization lab module on Canvas and submit the pre-lab quiz.
¬   Then go to Late Nite Labs and complete all of the Biochemical Characterization lab activities.
¬   Once you are comfortable with all of the material covered in this document and with all of the lab activities, go to Late Nite Labs and submit the Biochemical Characterization multiple choice quiz.

NOTES:

•   There is a question on the Late Nite Labs multiple choice quiz that shows a picture with “GEL” below it. The substance in that picture is a LIQUIFIED substance.

Explanation / Answer

Answer:

If you see a test tube with a column of oxygen bubbles forming, what test is being performed? Describe the reaction that takes place during this test.

•   If you see a purple tube during an oxidase test, what can you conclude about the reaction?

•   How do bacteria metabolize molecules too large to enter the cell?

•   What is indicated by a clearing around bacterial growth in Tributyrin Agar?

•   What color will a specimen turn during an Indole production test if it is positive for Indole production?

•   Why are organisms usually MR or VP positive, but not both?

•   What color will a specimen turn in a citrate test if it is positive for citrase?

•   What is a reaction that can lead to the formation of precipitate in the sulfur reduction test?

•   What color is the precipitate in a sulfur reduction test?

•   How is urease activity detected?

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