Monday, February 22, 2016

Viruses and Bacteria

Chapter 18: Viruses and Bacteria 



Essay Prompt: Explain the Procedure of Infection of this Virus


How does this virus spread?




What classifies organisms as living?
Are viruses alive?
What makes up a virus?
How do viruses replicate?
What are some examples of viruses?



Viruses are not considered living because they do not meet these characteristics...but once in a host they hijack the its machinery to create more of the virus.

Many viruses have a similar composition of protein and nucelic acid. (some have a lipid coat)



A viruses can replicate using 2 cycle processes:
Lytic Cycle where the cell bursts, killing the host cell.

Lysogenic Cycle where the viral DNA is integrated into the host DNA. External factors (stress conditions) may trigger the virus into going into the Lytic Cycle.




What are some examples of viruses?


Ebola: fatality rate of up to 90%, the Ebola Virus Disease (also called Ebola Hemorrhagic Fever) is believed to be one of the deadliest virus infection all over the world.


















Rabies Viruscauses 55,000 human deaths each year, if left untreated 100% fatality rate.











Smallpox Virus: very few deaths due to a vaccine but if patients contract the virus 90% fatality rate .






















Chickenpox Virus: (varicella) used to be very common in the United States before the chickenpox vaccine became available in 1995. In the early 1990s, an average of 4 million people got chickenpox, 10,500 to 13,000 were hospitalized (range, 8,000 to 18,000), and 100 to 150 died each year.















HIV: this virus has claimed the lives of millions. In many cases if no treatment/medication 100% fatality.















SARS: Severe Acute Respiratory Syndrome about 10% fatality rate.



Rhinovirus


How do you get the Common Cold

Influenza



Avian Flu







Viroids: nucleic acid molecule that infects plants




Prions: protein molecule that infects the hosts neurological system
Mad Cow Disease

Zika virus




Are you controlled by viruses


Prokaryotes

Characteristics:

  • no membrane bound organelles
  • free floating DNA in circular form and/or a plasmid (separate part of DNA)
  • unicellular
  • motile (movement) by use of flagella and/or pili



Groups of Prokaryotes

  • Obligate anaerobes can not survive in the presence of O2
  • Obligate aerobes must have O2 to survive
  • Facultative aerobes are can survive in the presence or absence of O2.
Archaebacteria vary in shapes and live in extreme environments

There are 3 types of structures of Eubacteria.



Rod shape - Bacilli 
Spiral shape - Spirilla
Spherical shape - Cocci




Reproduction/Conjugation

Bacteria reproduce sexually using their pili



They can also reproduce asexually through  BINARY FISSION.


Gram Staining

Gram Negative Bacteria have the extra layer of protection which makes them harder to treat. Their cell walls are resistant to several classes of antibiotics.


Benefits/Treatments
Some bacteria inside our bodies are beneficial. They help organisms breakdown food. Some make vitamins and other compounds.

They have a mutualistic symbiosis with organisms. Bacteria breakdown food and keep them healthy, while organisms protect them.

Bacteria can be treated with Antibiotics. 

Image result for antibiotics

EXAMPLES

E.coli & Salmonella= cause food poisoning
 


H.Pylori= cause ulcers and gastritis

Staphylococcus aureus= causes a variety of infections in the body, including boils, cellulitis, abscesses, wound infections, toxic shock syndrome, pneumonia, and food poisoning

Image result for Staphylococcus aureus

Streptococcus pyogenes = strept throat


Nactrotizing fasciitis Flesh eating bacteria

 








Leprocy




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