answer ch 7 college chemistry Essay

Submitted By donnabottineau
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Lab 2 Report
Gram Staining
40X cell wall
Gram positive

Gram negative this cheek cell is A cluster and its Shape is cocci

Gram positive

Gram negative

400X Nucleus
Gram positive

Gram negative

1. Describe, in detail, the differences in the gram + and gram - bacterial cell membranes. Include number of layers, what each layer is made of, the charge on the membrane etc.

The difference between the gram negative and gram positive are. Gram positive cells contain 3 layers. The first layer are thick layers of peptidoglycan (cell wall), this prevents the cell from lysing. The peptidoglycan contains teichoic acids and lipoteichoic acids. Next you have the gel like material, and the cytoplasmic membrane. With a gram positive staining the cell will dye purple, dye will then dehydrate the cell trapping it and making it hard for it to get out. Gram positive are easier to treat.
Whereas the gram negative are more complex made up of 6 layers or more. They have a thin peptidoglycan that are surrounded by an outer membrane (lipid bilayer), the outer layer of the membrane is lipopolysaccharide they are a live bacteria that protects the cell and stops things from entering such as substances. Next you have the periplasm, the lipoprotein and cytoplasmic membrane (inner membrane lipid bilayer). Gram negative have Lipid A which is an immune defence preventing thing from entering. When staining a gram negative it will turn pink otherwise they would be clear. The Gram negative cells are harder to treat

2. Discuss, at each step of the staining process, how gram + and gram – bacterial behave differently and why.

In each step of the staining process this is how the gram negative and gram positive behaved with each other.
Step one: the gram negatives and gram positives are the same with a little black. Because you are just fixing it.
Step two: colour though out the cells, with gram negative a little lighter.
Step three: The same in this step.
Step four: Gram negative is stripped of the colour where gram positive keeps colour. This is because it is alcohol and the gram positive dehydrates after the crystal violet and making it hard to get out whereas the gram negative is not like that it does not hold the dye you need special dye for this procedure.
Step five: The gram negative dyed pink and the gram positive dyed purple.

3. Discuss the