Bacteria are the most widely distributed organisms in the biosphere. They are found in all different types of soil, water and even in the bodies of other living organisms. Every single place that humans have explored on the Earth, have shown to contain microbes.
Bacteria are living organisms and like all living organisms, they require energy and carbon sources in order to metabolize and reproduce. And like all living organisms they respond to changes in their environment.
Ubiquity is defined as the state of being everywhere all the time. In this lab you will test the idea that microbes are ubiquitous or present everywhere at all times.
Materials
One Triptic Soy Agar (TSA) plate per student
One sterile swab
Procedure
1. Decide on an area to test for the ubiquity of microbes. List your area on the white board in front of the classroom.
2. Obtain one TSA plate and label it on the bottom (side with the agar) with your name, class section and the surface you will sample.
3. Obtain one sterile swab.
4. To obtain a sample, roll the sterile swab back and forth across the area you wish to sample. If the area you are sampling is dry, you will need to wet the swab with distilled water before you obtain a sample from that area.
5. To inoculate the agar, roll the swab gently across the surface of the agar plate. Do not break the surface of the agar.
6. When you are finished, dispose of the swab in the biohazard container and place the inoculated TSA plate upside down in the 37°C incubator.
7. Incubate the plates for 48 hours.
8. After incubation, observe the plates for microbial growth
Name Biology 274 Section D030
Lab 1 – Ubiquity of Microbes
Complete the following table.
Source of microbes: Sink Faucet
Colony Type 1
Total # on plate ____________
Colony Type 2
Total # on plate ____________
White Board
Toilet
Mouth
Overall Colony Appearance
No growth
No growth
No growth
Many colonies/punctiform