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Cumpas, Jerome C.

HUB 44

1. HIV destroys CD4 positive T cells, which are white blood cells crucial to maintaining the function of the human immune system. As HIV attacks these cells, the person infected with the virus is less equipped to fight off infection and disease, ultimately resulting in the development of AIDS.

2. The basic principle of Gram staining is the properties of certain bacteria cell walls to retain the crystal violet dye. The cell walls for Gram-positive microorganisms have a higher peptidoglycan and lower lipid content than Gram-negative bacteria.

For the acid fast staining. When the smear is stained with carbol fuchsin, it solubilizes the lipoidal material present in the Mycobacterial cell wall but by the application of heat, carbol fuchsin further penetrates through lipoidal wall and enters into cytoplasm. Then after all cell appears red. Then the smear is decolorized with decolorizing agent (3% HCL in 95% alcohol) but the acid fast cells are resistant due to the presence of large amount of lipoidal material in their cell wall which prevents the penetration of decolorizing solution.

3. Magnetosome chains are membranous prokaryotic structures present in magnetotactic bacteria. They contain 15 to 20 magnetite crystals that together act like a compass needle to orient magnetotactic bacteria in geomagnetic fields, thereby simplifying their search for their preferred microaerophilic environments.

4. Prokaryotic cells carry out cellular respiration within the cytoplasm or on the inner surfaces of the cells.

References:

https://www.niaid.nih.gov/topics/hivaids/understanding/howhivcausesaids/Pages/cause.aspx

http://www.gbiosciences.com/PDF/Protocol/202_Bacterial_Gram_Staining_TEACHER.pdf

http://www.microbiologyinfo.com/acid-fast-stain-principle-procedure-interpretation-and-examples/

https://en.wikipedia.org/wiki/Magnetosome

http://hyperphysics.phy-astr.gsu.edu/hbase/biology/celres.html