The Effects of Black Tea on the Growth of E. Coli Bacteria Cultures

he experimental variable in this experiment was the changing number of Alka Seltzer tablets that were put into the 250mL beaker of vinegar. Some of the control variables in this experiment were that the same beaker and thermometer were used for each trial, the same type of vinegar and Alka Seltzer were used for each trial, and the same amount of vinegar. The original Hypothesis was that more Alka Seltzer would increase the temperature of the vinegar was not correct. After analyzing the data it can be seen that for the first trial the temperature did not change as it stayed at 24 degrees Celsius before and during the reaction with 1 tablet, also for trial two with two tablets the temperature stayed the same at 23 degrees Celsius and did

During the purification section of this lab, the LB/amp/ara agar plate was examined for well-isolated green colonies and the LB/amp plate was observed for white colonies with space between each other. These colonies were circled on the outside of the plates using a marker. Next, two 15 milliliter culture tubes containing 2 milliliters of nutrient growth media were obtained and labeled “+” and “-“. Using a new inoculation tube, the circled colonies from each plate were scooped out and immersed in their respective culture tubes. Once the bacteria was mixed into the solution, the tubes were sealed and placed horizontally into the 32⁰ incubator for 24 hours.

And finally into test tube 3, I pipetted 1.0 ml turnip extract and 4.0 ml of water. The contents of test tube 1 was poured into a spectrometer tube and labeled it “B” for blank. “B” tube was now inserted it into the spectrometer. An adjustment to the control knob was made to zero the absorbance reading on the spectrometer since one cannot continue the experiment if the spectrometer is not zeroed. A combination of two people and a stop watch was now needed to not only record the time of the reaction, but to mix the reagents in a precise and accurate manner. As my partner recorded the time, I quickly poured tube 3 into tube 2. I then poured tube 2 into the experiment spectrometer tube labeled “E” and inserted it into the spectrometer. A partner then recorded the absorbance reading for every 20 seconds for a total of 120 seconds. After the experiment, a brown color in the tube should be observed to indicate the reaction was carried out. Using sterile techniques, any excess liquid left was disposed

The pipette was used to transfer 8 mL of the 0.5 molarity solution into the graduated cylinder. Distilled water was added to raise the bottom of the meniscus to the 20.0 mL line and the solution was transferred into the beaker after it was rinsed with the solution. The pipette was used to take a small quantity of the solution and rinse and then fill a test tube with the solution. The amount of 0.2 molarity solution needed to create 20.0 mL of 0.1 molarity solution was calculated as 10.0 mL. The pipette was used to transfer 10.0 mL of 0.2 molarity solution into the graduated cylinder and distilled water added until the bottom of the meniscus reached the 20.0 mL line. The solution was transferred to the rinsed beaker and then a portion placed into a test tube that had been rinsed with the solution. The amount of 0.1 molarity solution required to create 20.0 mL of 0.05 molarity solution was calculated to be 10.0 mL. The pipette was used to transfer 10.0 mL of 0.2 molarity solution into the graduated cylinder and distilled water added until the bottom of the meniscus reached the 20.0 mL line. The solution was then placed into a beaker that had been rinsed with the solution and then into a rinsed test

Beakers 5-8 were set aside for later use. I then recorded by observation of beaker 1 in Table 1 on the Lab Reporting Form; this included smell, color, etc. 10 mL of vegetable oil was added to beaker 2, 10 mL of vinegar to beaker 3, and 10 mL of liquid laundry detergent to beaker 4. Each beaker was mixed thoroughly with a wooden stir stick. My observations such as color and smell were annotated in Table 1 on the Lab Reporting Form. Next, I cut the cheesecloth into five different pieces. I took one piece of cheesecloth and folded it so it was 4 layers thick. I then placed it into the funnel. 60 mL of soil was measured out using the 100 mL beaker and placed into the cheesecloth lined funnel. The funnel was then put inside beaker 5. The contents of beaker 1 (water) were poured through the funnel and let filter for 1 minute into beaker 5. My observations were recorded on Table 1 on the Lab Reporting Form. I repeated the process of creating a filter of cheesecloth and soil and filtered the contents of beaker 2 (vegetable oil) into beaker 6, beaker 3 (vinegar) to beaker 7, and beaker 4 (detergent) to beaker 8. All observations were recorded on Table 1.

The first result of importance was the result of the Gram stain. The observations of the unknown bacteria from the slant culture after Gram staining showed that the unknown bacteria were Gram negative bacilli (Image 1). After determining the unknown bacteria was Gram negative, an oxidase test was conducted on a sample from the slant culture. The cotton swap with the sample of bacteria did not change color when the oxidase reagent was applied, thus providing a negative result. With a negative oxidase test, further tests were conducted to determine various characteristics of the unknown bacteria. A MR-VP broth was inoculated with a sample from a slant culture of unknown bacteria. After incubation, the methyl red reagent was added to the broth, and the broth turned red, providing a positive result (Image 2). An EMB agar streak plate was inoculated with a sample from a slant culture of the unknown bacteria, and after incubation, growth was found on the plate, providing a positive result (Image 3). A Citrate agar slant was inoculated, and after incubation, growth was found on the media, providing a positive result (Image 4). A Urea agar slant was inoculated, and after incubation, the agar had changed from a peach color to a bright pink color, providing a positive result (Image 5). Using the flowchart (Figure 1) developed from the Table of Expected Results, the lab partners started at the oxidase test. Given the negative result of the oxidase test, the flowchart is

A total of 13 tests were performed on the unknown bacteria culture #1. Two tests were inconclusive and could not be used. The first test was simply the phenylethyl alcohol agar (PAA) to check for contamination because of its selectivity towards gram-positive bacteria. The alcohol in the agar penetrates the thin peptidoglycan wall of gram-negative bacteria, which results in a slowed and stopped growth. The mannitol salts agar (MSA) is a differential test due to the mannitol sugar. It also has high amounts of salt (7.5% NaCl). If the organism can ferment the sugar, and produce acid as a result, the phenol red pH indicator dye will turn yellow due to the acidic environment. If no change occurred, then it is a negative result meaning that the bacteria

In part II of the lab six small glass tubes were obtained in a test tube rack. Ten drops of distilled water were then added to test tube 1, five drops to tubes 2-4, and no drops in tubes 5 and 6. Five drops of 0.1M HCl were added to test tube 5 and five drops of 0.1M NaOH to test tube 6. Five drops of enzyme were then added to all tubes except tube 1. Tube 3 was then placed in the ice bucket and tube 4 was placed in the hot bucket at 80-900C for five minutes, the remaining tubes were left in the test tube rack. After the five minutes five drops of 1% starch was added to every tube and left to sit for ten minutes. After ten minutes five drops of DNSA were then added to all the tubes. All the tubes were then taken and placed in the

A urea hydrolysis test was performed. A nitrate reduction was performed. The bacterial unknown was grown on Kigler 's iron agar media, MSA media, soy agar media, PEA agar media, EMB media, and SIM medium media. A gram stain was performed. A methyl red test was performed. A Voges-Proskauer test was performed. A citrate test was performed. A motility test was performed. A gelatin hydrolysis test was performed. A liquid broth agar was cultured to determine if there was use of oxygen.

The purpose of the experiment was to compare antacids by the amounts acid they neutralize to find the most effective antacid. Finding the most effective antacid is important because it will help others by allowing them to choose the best product for their heartburn. Titration is the process of which the unknown solutions concentration reacts with a known solution concentration. During the experiment, titration was used to calculate the moles of HCl neutralized by the antacid in this case was gelusil, by knowing the moles of HCl initially added to the flask and moles of HCl neutralized by the NaOH.

The validity of my experiment is invalid as looking back on how I performed the experiment, I would say that I made one mistakes that I believe would have affected the overall result. This mistake is not waiting long enough for the water to dry on the sprayed agar plates. By not waiting long enough, the water would still carry bacteria. Meaning that even though it wouldn’t be there when the water dried, it was still there when I ran the swab over the top of it.

To start off the experiment 25mL of water was placed into a labeled beaker and tested for the pH using pH test strips. Next the antacid tablet was placed in the solution and timed for how long it took to dissolve the tablet. Finally the temperature was measured. This same process was repeated for the acidic solution, and finally for the basic solution. After each experiment the pH, the reaction time, and the temperature of the beaker were recorded into a table. For this experiment the independent variable was the substance used (acid, neutral or base), and the dependent variable was the reaction time of each substance. The constant conditions of this experiment included the amount of substance being used, and the placing of one antacid tablet into each beaker. The experimental group was the acidic and basic solution, and the control group was the neutral

We took the plastic cup and added the stir bar into it, then we inserted the plastic cup and the stir bar into the styrofoam cup. Next, we secured the clamp on the ring stand rod, and then added the solution calorimeter to the other end of the clamp. Following that, we took the beaker and filled it with distilled water and transferred it to the graduated cylinder. Then we poured it into the plastic cup with the stir bar in it. We turned the stir plate to number 6 and let the water stir around for 10 seconds, then we added in our first effervescent tablet and let it for about a minute or until it was fully dissolved. We added an extra tablet to every test until we reached the total number of tablets we could insert which was 5. After we were finished with each test, we washed out plastic cup, the solution calorimeter, and the stir

The purpose of the two experiments was to determine the fundamental effects that temperature has on the growth and survival of bacteria. During the first experiment five different bacterial broth cultures of Escherichia coli, Pseudomonas fluorescens, Enterococcus faecalis, Bacillus subtilis and Bacillus stearothermophilus were individually incubated at temperatures of 5, 25, 37, 45 and 55°C for one week in an aim to distinguish the effect temperature has on growth and survival of the five different species. After one week they were observed for distinguishable changes by the turbidity showing an indication of bacterial growth, or the clarity an indication of no survival.

A fresh pipette was used to transfer 0.5ml of broth culture of E. coli, to be inoculated, into a tube of molten agar previously boiled to drive off oxygen. The tube was then rolled to distribute the bacteria and allowed time for the agar to harden. The tube was incubated at 37oC for 48 hours. The procedure was repeated for broth cultures of the bacterium Clostridium sporogenes and B. Subtilis.