12 Agar Plates Lab Report

For this experiment you will need 39 agar plates, sterile cotton swabs, a concentrated amount of Escherichia coli (E. coli), three different levels of antibiotic (Ampicillin: 1mg, 5mg, and 10mg), a bunsen burner, metal tweezers, an incubator, 27 broths, and a ruler which should all be provided through your laboratory. For the first generation, you will be using 12 plates. Three of the plates will be labeled G1 control, three of the plates will be labeled G1/1 mg, three plates will be labeled G1/5 mg, and the last three plates will be labeled G1/10 mg. Then you will dip a sterile cotton swab into the E. coli solution and you will streak one of the twelve agar plates. Repeat this step with a new cotton swab each time until all the plates have been streaked with
Once cooled, open one of the ampicillin tubes and grab the susceptibility ring with the tweezers. Make sure the ring is the corresponding dosage to the plate it is going to be placed on. Try to keep the susceptibility ring as close to the center of the agar plate as possible. The amount of Ampicillin used for each plate is the independent variable and the plate labeled G1 plate 1, which will be without the susceptibility ring, will be your control colony. Allow the colonies to grow and the antibiotic to work by incubating the plates at 37 degrees Celsius for 48 hours. After 48 hour growth period, you will return to the plates and measure the zone of inhibition for each plate and record this data. The size of the zone of inhibition will be the dependent variable. To start your second generation you will need to take a sterile cotton swab and collect the E. coli closest to the zone of inhibition from each G1 plate and transfer it to a broth. Swish the cotton swab with the E. coli in the broth and then swab your corresponding G2 plates. These agar plates will be labeled the same way as the original plates, but the plates will now say G2 plate 1,