After isolating different species of bacteria, you see two distinct types of col

Question

After isolating different species of bacteria, you see two distinct types of colonies.

-One has medium-sized shiny colonies that are mucoid with entire margins, convex elevation and a whitish translucent appearance. This colony type is the dominant type on the plate.

            -The other has circular, pinhead colonies which are convex with entire margins

and have a yellowish-white color. There are only 2 colonies that appear this way.

You make a pure culture of each type of colony using half of one colony, labeled with its colony description. You take the other half of the colony you used to make your pure culture, and perform a simple stain to determine the size and shape of the different bacteria.

4. What kind of simple stain would you perform and why? What color will the cells appear when looking through the microscope and why?

5. Do you think the cells’ shape has been affected by the stain? Why or why not?

6. You determine that the cells from the whitish translucent colony are rod shaped. What term do you use to describe this cell type? ____________

You find that the cells from the smaller, yellowish-white colonies are circular and seem to appear in clumps. What cell type is this? ________________

Explanation / Answer

The basic test to identify the different group of bacteria could be Gram staining.Gram staining differentiates bacteria by the chemical and physical properties of their cell walls by detecting peptidoglycan, which is present in a thick layer in Gram-positive bacteria.In a Gram stain test, Gram-positive bacteria retain the crystal violet dye, while a counterstain (commonly safranin or fuchsine) added after the crystal violet gives all Gram-negative bacteria a red or pink coloring.

Gram staining doesnt affect the cell's shape.

Rod shaped bacteria are called as Bacillus while the clumps could be the Staphylococcus.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.