The effect of antibiotics on E. coli
In this experiment, we are testing the effectiveness of four new substances extracted from certain molds. The effects of these substances on the E. coli bacteria could prove to have some antibiotic properties. I believe that all the substances, as compared to the control, will possess some antibiotic properties. In this experiment, the zone of inhibition around the substances P-10, S-10, C-30, and TE-30 will be measured against a control substance. Certain variables will be controlled during this experiment including but not limited to the concentration of the E. coli bacteria used, the temperature and time allowed for the bacteria to grow, the same size disks containing the aforementioned substances and control will be used, and the same media will mixed with the E. coli bacteria to ensure that all the substances tested will have experienced the exact same conditions. A blank disk will be used in each Petri dish to serve as the control. The paper disk itself is not thought to possess any antibiotic properties.
The following steps were taken to complete the experiment:
On the first day,
Obtain a Petri dish (keep it closed), a vial of medium, a bacteria culture tube with Escherichia coli, a sterile 1mL pipette and a mechanical pipette pump.
Measure 1mL of bacteria with the pipette and pump. Then add 1mL to the culture media.
Gently swirl the media and bacteria, then pour the media into a sterile Petri dish. Label the top of the dish with initials.
After 45 minutes or more, the media should have solidified. Add of the 4 substance disk and a control disk to the surface of the medium using sterile forceps. Arrange the disks so that they are widely separated.
After one week,
Measure the greatest diameter of the zone of inhibition for each disk. Be sure that the measure includes the disk itself. Record the number in mm.
Each Petri dish should be measured and recorded independently in a table.
Calculate the data to...