Unknown Identification Lab Report: Bacterial Culture

Unknown identification:
Students will also be given a bacterial culture to identify. Most of these will be organisms we have used
in exercises. ALL students will perform 5 tests in total: a Gram stain, fermentation tests (fermentation
tests for glucose, sucrose, and lactose are considered a single test), and then 3 other tests (enzymatic or
selective/differential media) on the unknown sample (these are selected by the student, must represent
logical/critical thinking for which tests are to be performed, and MUST be approved by Ms. Williams
prior to being performed). A handout titled “Ms. Williams' Unknown Record sheet” MUST be used when
performing and recording data for your unknown tests. ALL test results MUST be shown to Ms.
Williams. A final report for the unknown identification must be turned in as a LAB REPORT by the date
stated in the class schedule. Unknowns are graded in two parts:
(i) 50 points for technique performance. For each test you perform incorrectly 5 points will be
deducted from the 50 points (example: you have to perform the gram stain 2 times to get it
correct = 5 points lost for the first incorrect result; have to perform the gram stain three times
= 10 points lost for the first and second incorrect results). This section is designed to assess
your ability to perform the techniques you have learned in the course.
(ii) 50 points for the laboratory report. Follow instructions below that give specific requirements for
each section (the bold blue percentages shown after the section title represent how much that
section is worth of the grade for the lab report):
 INTRODUCTION (15%): The introduction will only include a description of the tests performed:
the principle (biology) of the test, and how to interpret ALL possible results for that test. For example,
with the gram stain, you would discuss that the gram stain identifies the differences between two cell
wall types, the structures of the two cell wall types, how each cell wall type is detected/identified in
the gram stain, and how the gram stain is also used for observing cell morphology. Do NOT include
any methodology of the tests in the introduction. You CANNOT state what your organism is or its
importance in the introduction. You cannot “ramble” on about how identifying organisms is important,
only discuss the tests you performed as described above. This section must be between half to one and
a half pages/sides long. This is to allow you to discuss each of the tests you performed in the required
detail.
 OBJECTIVE (5%): You will have a single objective (to identify the unknown organism).
 HYPOTHESIS (10%): You will have a single, broad hypothesis. Hypotheses are written before you
start any work, so you cannot state what tests you will use, as you do not know that until you have the
results of the first tests. You cannot state what organism will be identified at the end either, as you
have no way of knowing this information before you start.
 MATERIALS/PROCEDURE (5%): The materials will be a paragraph list for all tests. The
procedure will be a 3-5 line summary of the chronological order you performed the tests in and which
tests required repeating. If you changed any parts of the procedure compared to the method(s) in the
laboratory manual for any of the tests, then you MUST give detailed information of how it was
changed. If you had to repeat any tests, then list that here.
 RESULTS (15%): The results section MUST be a table of ALL the results. There will be no images
Required Texts (BOTH lab books are required and are available in the Clarkston campus
bookstore):
1. Mcallister, Carl F., 2011. Manual for Microbiology Laboratory 3rd ed., (this is a GPC published
laboratory manual and thus no ISBN)
2. Leboffe & Pierce, 2011. Photographic Atlas for the Microbiology Laboratory, 4th edition.
Please use these two books as extra two sources, making it total of five sources.