Gram Test Lab Report Essay

An unknown bacterium was handed out by Dr. Honer. The appropriate tests were prepared and applied. The first procedure that was done was the gram stain. Under a microscope, if the gram stain is purple, the bacterium is gram positive, if the stain is red, it is gram negative. The next test was the fermentation tests for glucose, sucrose and

The next step of the project included preparing a Gram stain to discover the cell shape, arrangement, and if the bacteria is gram positive or

This means that the bacteria for this lawn have cells that are surrounded by a cell wall which includes a thin layer of peptidoglycan and surrounding that is an outer lipid membrane that does not contain the Gram strain. Yet at the same time while Kanamycin was the most effective the Ampicillin and Penicillin had reactions as well. The Ampicillin would kill both Gram-positive and Gram-negative so this could indicate that there are Gram-negative bacteria in the lawn, but the fact that the Penicillin worked as well was what was interesting. This means that this bacterial lawn contains both gram-positive and gram-negative bacteria. Gram-positive are bacteria with cell walls that contain a thick layer of peptiodoglycan that retains the Gram strain. For plate 2, trashcan lid, only the Kanamcyin worked which indicates that the only bacteria in this lawn are Gram-negative, but if that is true why didn't the Ampicillin work at all? Ampicillin works to kill both positive and negative grams, but there was no reaction this time. Could it be that it needs more

Lab Day 1: After receiving my unknown bacteria, I streaked a TSA plate and incubated at 37°C for 48 hours. I then picked a single colony from the plate with my sterile loop and streaked a TSA slant and labeled it “Working Stock”. I did the same with another TSA slant and label the second one “Back-up Stock”. This would be the samples I used to complete the following procedures through the next four weeks to determine my unknown bacteria.

After the broth is mixed and the inoculating loop is cooled, take the cap off of the broth culture tube by using the two fingers, on your writing hand, that are not holding the inoculating loop.

General Biology Bryarra Tinoco BIO102 - Spring Semester – 2015 February 24, 2015 Introduction For this lab the experiment was to test how effective the antibiotic properties were in four substances. The hypothesis that I conducted for this lab was that if the disks containing the substances had a zone of inhibition then the antibiotic effect could be measured and compared.

In this process, I am determined to know my unknown bacteria. So I start by inoculating my unknown bacteria, and spread it on the surface of my EMB medium agar, I take the EMB medium and place it on my incubator chamber. I will get my result on the following day. When the day comes, I walk to the incubator to take out my result, and I found out that it is showing shining green culture on top of the agar. I notice that it is a positive result, and I follow through the dichotomous key, which help me to separate the bacteria from others base on this characteristic. EMB test for Gram-negative bacteria because it has a built-in lactose fermentation that allow them to grow. I make another culture of the unknown bacteria for the following day.

Name this Procedure  Identify the two types of bacteria present by shape and gram stain. In a gram stain what is the primary stain?

To aseptically transfer bacteria from an unknown to a tube of liquid broth you have to flame the loop or wire before you begin to sterilize it. You then remove the caps from the tubes and flame the mouths of the tubes to prevent air-borne contamination. When all this is done, you have to pick up the inoculum or unknown culture by running the sterile loop or wire down into the tube. Once you got the inoculum you drop it into the sterile medium to inoculate it.

The most difficult part of the experiment was separating the Gram positive from the Gram negative. I knew my Gram negative was rod-shaped and my Gram positive was coccus-shaped. I had to spend 2 days streaking many plates trying to isolate my two bacteria. The morphology of both were very similar and it was difficult to tell the difference until I was able dilute the colonies by streaking TSA plates multiple times.

Bio Pre Proposal I. OBJECTIVE: To have the ability to identify gram positive and gram negative cells and understand how the staining affects them. II. HYPOTHESIS: if a smear of both Escherichia coli and Staphylococcus epidermidis are stained, then gram negative and gram positive stains should result respectively and be identifiable under the microscope due to the structure of the cell walls. III. PROCEDURE: 1.

The structure of the organism’s cell wall determines whether the organism is gram positive or negative when stained. In addition, staining also allows for one to identify cell size, shape and arrangement. Gram-positive cells have a thicker peptidoglycan cell wall to which the stains are

For this lab we used two microcentrifuge tubes, a pair of vinyl gloves to prevent contamination, a micropipetter, six sterile micropipetter tips, 500 µl of a transformation solution containing CaCl2, seven sterile loops, ice, a timer, a 42°C water bath, a floating rack two colonies of E. Coli bacteria, pGLO plasmid DNA, four Luria Bertani (LB) broth nutrient agar plates (one with LB alone, two with LB and ampicillin, and one with LB, ampicillin, and arabinose), 500 µl of LB nutrient broth, tape, a UV light, and a 37°C incubator.

The petri dish lid was raised to insert the loop. The loop was touched to the agar area on the opposite side of the dish. The bacteria on the loop were transferred to the agar. The bacteria were spread in the first sector of the petri dish by moving the loop back and forth across the dish (zigzag motion).

7. Using a new inoculating loop, add one loop-ful of plasmid DNA to the +plasmid tube, mix it in the tube, and return it to ice for 15 minutes.