Sunday, June 3, 2012

Anatomy and Physiology: Different Pathogens




A cholera bacterium.

Bacteria
Bacteria can adapt very well to environment that change constantly because they have short generation spans.  During these short generation spans, they can undergo genetic recombination.  This way, so when they reproduce through various ways such as transformation, transduction, and conjugation, the new DNA will replicate along with their own original DNA.  These new, foreign DNA are expressed in the new strains of transformed bacteria.  This also lets each bacterium adapt their metabolic processes with the changes of their environment.

The structure of the HIV virus.


Virus
Unlike bacteria, virus are not actually alive because they cannot survive outside a host.  They are basically just genes in a protective coat.  The parts of a virus includes its capsid, protein coat, viral envelope, and nucleic acid.  Bacteriophages are the group of viruses that can infect bacteria.  They reproduce through the lytic and lysogenic cycles.  In the lytic cycle, they attack the host cell and when the cell bursts, the new viruses move on to destroy other host cells.  In the lysogenic cycle, the virus may lie in wait in the host cell for a long time before the lytic cycle is activated and it destroys the host cell.

The structure of a prion.

Prion
Prions are simple infectious agents.  They are protein that is misfolded but have no genetic material.  Although they are proteins, they can reproduce on their own and become infectious agents.  In humans, they may have been linked with the Creutzfeldt-Jakob Disease (CJD) and the Gerstmann-Straussler-Scheinker Syndrome.


Symptoms of hemophilia, a genetic disorder

Genetic


Genetic diseases are caused by an abnormality in person's genome.  This could result from a small mutation (ex: single base in DNA of a single gene) to a large mutation (ex: addition or deletion of entire chromosome).  Some genetic disorders are inherited from the parents but some are also caused by acquired changes and mutations in the genes.  An example of a genetic disease is hemophilia, which is sex-linked.


Lung infected with black lung disease.




Environmental


Environmental diseases are caused by factors in the environments, such as pesticides, chemicals, radiation, and pollution.The chance of a person developing a environmental disease depends on the dangers of their environment and their genetic susceptibility to certain dangers.  For example, coal miners are more susceptible to black lung due to the inhalation of dust.  Proper safeguard can prevent environmental disease.


Rash caused by Lyme disease.


Invertebrates


Some diseases are caused by invertebrates.  Many invertebrates carry diseases; for example, mosquitoes often carry and spread yellow fever and malaria.  Some of these disease-causing invertebrates are parasitic.  One example are ticks, which can cause Lyme disease.

Sources:
http://www.trupela.com/wp-content/uploads/2009/09/cholera-bacteria.jpg
http://www.scientificamerican.com/media/inline/F1C30FB9-F95F-8B4E-9FAF03A0503D1ABA_1.jpg
http://www.flickr.com/photos/ajc1/464066753/
http://www.doctortipster.com/wp-content/uploads/2011/11/Hemophilia-Symptoms.jpg
http://images.paraorkut.com/img/health/images/b/black_lung-580.jpg
http://images.paraorkut.com/img/health/images/l/lyme_disease_rash-55.jpg
http://www.medicinenet.com/genetic_disease/article.htm
http://www.humanillnesses.com/original/E-Ga/Environmental-Diseases.html#b

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