Bacterial Morphology

Bacterial Morphology and Staining Techniques

A.  Write a lab report about the “Bacterial Morphology and Staining Techniques” lab kit experiment in which you do the following:

1.  Explain how the differences in cell wall structures of gram-positive and gram-negative bacteria cause them to stain differently with the Gram stain.


The explanation from part A1 belongs in the introduction section of the lab report.

2.  Describe the purpose of each of the four basic steps of Gram staining.


The description from part A2 belongs in the materials and methods section of the lab report.
3.  Describe the images of Staphylococcus epidermidis and Escherichia coli provided at the web links below, including the color and morphology of each organism.

a.  Identify each organism from part A3 as either gram-positive or gram-negative.


These images are accessible through the Escherichia coli Gram Stain Image and Stapylococcus epidermidis Gram Stain Image web links below.


The description from part A3 and the identification from part A3a belong in the results section of the lab report.
4.  Discuss how the structure of gram-negative bacteria contributes to their ability to cause disease.


The discussion from part A4 belongs in the discussion section of the lab report.

Bacteria Staining Techniques

Ecoli Gram Stain

Staph Gram Stain