Biology HW 5/3/2012

Due on Wed. 5/9/2012

1) Read and taKE NOTES FOR CH 21 ON PLANTS, pgs 602 - 621.

2) finish Bacteria Lab into your lab Notebook

Classification of Bacteria Lab

Task:  As a group of ~4, you will attempt:

• to predict which unique location will produce the greatest number of microbes
• each student at your table will collect a single unique sample from the provided list
• to grow an assortment of microbial colonies on an agar plate
• use remarkable characteristics to identify different microbial colonies
• create a dichotomous key that identifies each unique colony

Question: Which unique location will produce the greatest number of microbes?

Hypothesis:  Make an educated prediction by discussing question and test with partners.

Test:  Pay attention to swipe and plating demo

Materials:  Agar plate (X), four swabs and one from the following list for each student (soil, compost, hands/nails, mouth, table, door handle, floor, sink, aquarium, …)

Procedures:  How will you use each material?  Record observation details of the swipe location.  Diagram the agar plate (X) before plating and after colonies have grown.

Data Table Examine the microbial colonies that form your data table will include qualitative responses to the following categories: 

1. Form - What is the basic shape of the colony? For example, circular, filamentous, etc.
2. Elevation - What is the cross sectional shape of the colony?.
3. Margin - What is the magnified shape of the edge of the colony?
4. Surface - How does the surface of the colony appear? For example, smooth, glistening, rough, dull, rugose (wrinkled), etc.
5. Opacity - For example, transparent, opaque, translucent, iridescent (changing colors in reflected light), etc.
6. Pigmentation - For example, white, buff, red, purple, etc.

·         Under no circumstance should you open the Petri dish lid to smell, touch or taste the microbes.

·         Observe the swipe location and anything else that might influence your experiment.

Analysis:  (Data Manipulation score on rubric X3 points)

1. make a dichotomous key that identifies each unique microbial colony
2. make a bar graph that displays an answer to the question for this lab
3. Which unique colony type grows in the most unique locations?

Conclusion:  Use the rubric

Bacteria: Each distinct circular colony should represent an individual bacterial cell or group that has divided repeatedly. Being kept in one place, the resulting cells have accumulated to form a visible patch. Most bacterial colonies appear white, cream, or yellow in color, and fairly circular in shape – irregular formed. Yeasts: Yeast colonies generally look similar to bacterial colonies. Some species, such as Candida, can grow as white patches with a glossy surface.  Filamentous & rhizoid forms. Molds: Molds are actually fungi, and they often appear whitish grey, with fuzzy edges. They usually turn into a different color, from the center outwards.  Filamentous & rhizoid forms.