Microscopy Lab Report

In order to start a stain, the microorganisms must be fixed to the microscope slide. This first step is called preparing a smear. Spread the specimen on a slide and let it air-dry. Once the specimen is dry it must then be heat fixed by waving the slide just one or two times over the flame. After this step is completed, the staining techniques begin. The Gram stain is considered a differential staining technique because it places bacteria into categories. The first step during the Gram staining technique is applying the primary stain, crystal violet, for twenty to sixty seconds. After this is completed, rinse with water and proceed to add the mordant stain, iodine, for one minute. The mordant

After allowing the two unknowns to incubate on the streak plate (Picture B), the next step was to gram stain, and hopefully separate them. After following the procedures for gram staining, and observing my slide underneath the microscope, it was evident that I had two microbes on my slide. One of the microbes was gram positive with a coccus shape, while the other was gram negative with a small rode looking shape to it (Picture A). The next step was to be able to separate them from each other using selective media. For the gram positive unknown, I used a MSA plate, which prevented gram negative growth. For the gram negative unknown, I used an EMB plate, which would inhibit any gram positive growth. The next class period on 4/18/17, my gram negative

It has been used for centuries to colour certain foods and fibres. More recently, the development of the chemical Sodium Hypochlorite, also known as household bleach, has been utilized to decolour materials. The reaction between the two is shown.

The stain was added to enable the observation of chromosomes as it helped to make them stand out under the microscope.

In the medical field, certain bacteria need specific antibiotic treatments and to find out what class the bacteria belongs to (whether if it is gram negative or positive) the specimen would have to undergo differential (Gram) staining. Hans Christian Gram was the Danish bacteriologist behind the gram staining technique. His Gram stain technique led to the discovery that Typhus bacillus did not retain the stain. Another procedure like differential staining is called simple staining. The main difference with this procedure is its simplicity and use of just one dye while the differential staining is more complex, uses more staining and helps shows cellular components of the bacteria. There are 3 bacteria that will be in use for the Gram staining.

While the bacillus is in the aging process some cells die and give the appearance of gram-negative bacteria; these are known as “gram-variable” (Tortora, 2013).

Gram staining, also known as Gram's method, is the most important and universally used staining technique in the microbiology and bacteriology laboratory. It is almost always the first test performed in the identification of bacteria (Xu, George).The

Furthermore, the stained check cells in Figure 2 under a magnification of 100 clearly identifies a cluster of check cells, positioned adjacent to the pointer. According to Figure 2, the stained check cells have apparently shown three cells, each with visibly distinct cell membrane and nucleus. The cell membrane is shown by the dark outline surrounding the cell, and the nucleus is the only visibly circular component within the cell. Although there are many other

A Gram-negative cell is pink when Gram-stained. Its cell wall is characterized by a relatively thin layer of peptidoglycan. There is no presence of teichoic acids. The layer of peptidoglycan is surrounded by an outer membrane; the outer layer of this membrane is lipopolysaccharide.

The students will duplicate cell diagram and will be able to recognize the structure and organelles of both plant and animal cells The students will also be able to describe

Gram staining-it is a technique used to differentiate between Gram-positive cells, which stain purple, and Gram-negative cells, which stain pink. The physical and chemical structures of these cells are different, allowing them to be identified by the used of different dyes. The first step is to color all the cells of the smear by using the basic dye crystal violet for 1 minute. Then iodine is used to bind the dye and make it less soluble, after it is rinse all cell remain

Gram positive bacteria is impenetrable to sanitizers because of its thick and well built plasma membrane which is thicker than most viruses and fungus cell’s membranes. This attribute gives great difficulty to alcohol antiseptics and is hard to destroy the proteins inside the cell because of the thick wall.

Another way to figure out if the sample is Gram-Positive or Gram-Negative are to see if it grows on certain mediums. If the sample grows on

The flattening of the onion root tips allows the chromosomes of each individual cell to be observed. The hydrochloric acid added, plays a part in fragmenting the root tissues by weakening and removing the bonds between cells so that each cell will not be attached to the other cell, obstructing the observation. Toluidine Blue solution acts as a colorant, giving a blue colour to the chromosomes and so that it is more easily spotted

After initial isolation a variety of techniques can be implemented to analyze and characterize the various microorganisms. The Gram Stain is a procedure that is performed in order to determine the difference between two main microbial cell wall types. Gram-positive cells have a cell wall made up mostly of a thick, peptidylglycan layer. These cells retain thecrystal violet color and the acetone alcohol acts as a dehydrating agent causing all peptidoglycan pores toclose and preventing the insoluble Crystal violet-Grams iodine complex from decolorizing. These cells appear PURPLE.