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Páginas: 2 (324 palabras) Publicado: 7 de enero de 2011
MICROBIOLOGY
Yanet Loyola.
BACTERIA: STUCTURE AND BEHAVIOR.
1. Which of the following is not found in all bacterial cells?
A) Cell membrane.
B) A nucleoid.C) Ribosomes.
D) Actin cytoskeleton. ( d is the correct answer)

2. Explain how the Gram stain differentiates two types of cells.
- Gram stain in used to differentiate bacterialspecies in two large groups: Gram-positive and Gram-negative based on the physical properties of their cell wall and how they react to the series of reagents applied to the cells. This procedure is basedin four steps; it begins adding crustal violet, where both cell walls affix the dye. The second step is adding gram’s iodine, and then alcohol is applied to dissolve lipids in the outer membrane andremove the dye from the peptidoglycan layer and the gram negative cell. Applying safranin is the final step. All this process permits differentiate the four major categories based on color reaction andshape.

3. What’s the medical significance of Bacterial spores?
-Bacterial spores are easily to survive in hostile environments otherwise not conductive to bacterial growth andreproduction. They are resistant to chemical and physical agents. Some of them persist in endospore and make an ideal candidate for bioterrorism. Also when the spores of this species are embedded in a woundthat contains dead tissue, they can germinate growth and release potent toxins.

4. What does bacterial chromosome do?
- Being bacterial chromosomes a circular body in bacteria that containsthe primary generic material, one of their major functions is to carry information required for bacterial maintenance and growth. They are the minimal generic requirement for bacterial survival.5. Describe most bacteria’s general shapes.
-Most bacteria have one of three general shapes based on the configuration of the cell wall: coccus( round), they have spherical or ball-shaped;...
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