Reference no: EM133362455

General Protocol:

Divide the agar side of the LB-agar plate to create 7 equal sections.

Label each section 1-7 as close as possible to the center of the agar plate so as to not obstruct your view of the bacterial growth.

Inoculate the LB-agar plate using a micropipette with 130 uL of the assignment liquid bacterial culture. Replace the Petri dish lid and dispose of the pipette tip.

Repeat for the second plate using the second bacterial culture.

Use a cell spreader to spread the bacteria evenly onto the agar surface.

USE OF THE CELL SPREADER:

Dip the cell spreader in ethanol.

Pass the spreader across the flame of the ethanol lamp. Make sure you only pass it through the flame and not keep it in the flame.

Once the ethanol has burned off, keep the spreader still for about 30 seconds. This allows the spreader to cool down before you start spreading the cells.

Once the spreader has cooled, use the spreader to evenly distribute the cell suspension over the entire surface of the plate. Use one hand to move the spreader back and forth. Use the other hand to turn the agar plate clockwise.

Return the cell spreader to the ethanol container without flaming, then repeat the same procedure until you have plated all the bacteria.

Replace the lids on the plates and leave the plates at room temperature until the liquid has been absorbed (about 10 minutes).

Sterilize the forceps using the same technique as before, and wait 30 seconds for the forceps to cool.

Using the sterilized forceps, apply the treatment discs on their respective sections of the agar plates, as close to the outer edge as possible. The corresponding numbers for all the treatments can be found in Table 1.

If infusing with an essential oil sample, carefully touch the filter disc to the surface of the liquid. The disc should not be fully submerged in the liquid. Allow any excess liquid to drip.

After placing the lid on your LB-agar plate for the last time, allow it to rest (agar side down) undisturbed for 5 minutes.

After the 5 minutes have elapsed, be sure to write instructor's name, lab section, the Gram status of your bacteria, and group number on the bottom edge of both agar plates.

Invert the plates, group both together using tape, label your tape with your group number and section number, and finally incubate the plates at 37 °C for 24 hours.

1. Which are the dependent and the independent variables?

2. What is/are the control(s)?

3. Will the data show a relationship between variables or a comparison?

4. Should you use a line graph or a bar graph? Explain why.

5. Make a rough draft of what you expect the graph to look like.