Viruses and Viruses and MoneraMoneraJessica JonesJessica Jones

Spring 2007Spring 2007

What do these diseases have What do these diseases have in common?in common?

Measles http://www.idph.state.il.us/images/measles.jpg

Mumps http://www.kcom.edu/faculty/chamberlain/Website/lectures/lecture/IMAGE/MUMPS.GIF

Polio http://www.immune.org.nz/site_resources/Professionals/Diseases/Polio/Polio.jpg

Hepatitis B http://www.idph.state.il.us/images/hepatitisb.jpg

It looks alive, acts alive… It looks alive, acts alive… but its not!but its not!

Viruses are Viruses are notnot living things. They differ living things. They differ from living things in several ways:from living things in several ways: They need to be inside a living organism to They need to be inside a living organism to

reproduce themselves.reproduce themselves. Outside the cell, they have no metabolism.Outside the cell, they have no metabolism. They do not have cell parts. (i.e. nucleus, They do not have cell parts. (i.e. nucleus,

mitochondria, etc)mitochondria, etc) They are composed of only a nucleic acid They are composed of only a nucleic acid

(DNA or RNA) inside a protein capsule.(DNA or RNA) inside a protein capsule.

Structure of a VirusStructure of a Virus

http://www.humanillnesses.com/images/hdc_0001_0001_0_img0008.jpg

DNA

(or RNA)

Protein capsid

Tube

Tail Fiber

http://mrsec.wisc.edu/Edetc/technologist/thumbnails/Matt/Virus_diagram.jpg

http://www.aidsactioncoalition.org/images/hiv_virus.gif

Viral ReproductionViral Reproduction In order to reproduce:In order to reproduce:

A virus attaches to a host cell.A virus attaches to a host cell. The virus injects the cell with its nucleic acid.The virus injects the cell with its nucleic acid. The viral nucleic acid commands the cell to make more The viral nucleic acid commands the cell to make more

viral protein and nucleic acid.viral protein and nucleic acid. The cell then ruptures, releasing hundreds of new The cell then ruptures, releasing hundreds of new

viruses.viruses.

http://porpax.bio.miami.edu/~cmallery/150/gene/sf11x1virus.jpg

No, they aren’t from the No, they aren’t from the 70’s.70’s. RetrovirusesRetroviruses

These are viruses that store their genetic These are viruses that store their genetic information as RNA.information as RNA.

Example: HIVExample: HIV

http://international.ucla.edu/cms/images/hiv_virus.jpg

How it How it works……works……

http://hiv.buffalo.edu/./images/hiv_virus_in_action.jpg

Kingdom Monera…your Kingdom Monera…your friendly bacteria.friendly bacteria. Bacteria are living, unicellular prokaryotes.Bacteria are living, unicellular prokaryotes. Divided into two kingdoms: Eubacteria and Divided into two kingdoms: Eubacteria and

ArchaebacteriaArchaebacteria Heterotroph or autotroph (most use Heterotroph or autotroph (most use

chemosynthesis).chemosynthesis). Types of Bacteria are classified based on Types of Bacteria are classified based on

their shape, type of cell wall, and their shape, type of cell wall, and movement.movement.

Bacteria have three basic shapes:Bacteria have three basic shapes: Bacilli – rod-shapedBacilli – rod-shaped Cocci – sphericalCocci – spherical Spirilla – spiral Spirilla – spiral

http://fig.cox.miami.edu/~cmallery/150/proceuc/c27x3proc_shapes.jpg

Structure of a BacteriaStructure of a BacteriaCell membrane

Cell wall

Ribosomes

DNA

http://www.ou.edu/class/pheidole/General%20Bacteria.jpg

Eubacteria have peptidoglycan and certain Eubacteria have peptidoglycan and certain specialized lipids in their cells walls that are not specialized lipids in their cells walls that are not present in Archaebacteria.present in Archaebacteria.

Gram staining is used to differentiate types of Gram staining is used to differentiate types of Eubacteria. Eubacteria. Those having thick cell walls will absorb more of the Those having thick cell walls will absorb more of the

dye and appear dark purple (Gram positive).dye and appear dark purple (Gram positive). Those having thinner cell walls will absorb less of Those having thinner cell walls will absorb less of

the dye and appear pink (Gram negative).the dye and appear pink (Gram negative).

http://bioweb.uwlax.edu/bio203/s2008/jaedike_alic/grainpositive.jpg http://www.asm.org/Division/c/photo/gc1.JPG

Bacteria Growth and Bacteria Growth and ReproductionReproduction Bacteria reproduce in two main Bacteria reproduce in two main

ways:ways: Binary fission – when a bacteria grows Binary fission – when a bacteria grows

to double its original size, it copies its to double its original size, it copies its DNA and divides, producing two DNA and divides, producing two identical cells.identical cells.

Conjugation – a hollow bridge is Conjugation – a hollow bridge is formed between 2 bacteria and genes formed between 2 bacteria and genes are transferred from one cell to the are transferred from one cell to the other.other. This creates genetic diversity within the This creates genetic diversity within the

population.population. Spore formation – when conditions are Spore formation – when conditions are

unfavorable (lack of food, drought) that unfavorable (lack of food, drought) that encloses its DNA and part of its encloses its DNA and part of its cytoplasm in a spore.cytoplasm in a spore. When conditions are better, the spore When conditions are better, the spore

will germinate, and the bacterium will will germinate, and the bacterium will continue to grow.continue to grow.

http://porpax.bio.miami.edu/~cmallery/150/gene/sf9x3box.jpg

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/69091a.jpg

We’re not all bad….We’re not all bad…. Bacteria are most widely known for Bacteria are most widely known for

causing diseases such as strep throat, causing diseases such as strep throat, tetanus, meningitis, and tuberculosis.tetanus, meningitis, and tuberculosis.

However, most bacteria are very useful:However, most bacteria are very useful: E. coliE. coli helps us digest our food. helps us digest our food. Many are important decomposers in our Many are important decomposers in our

ecosystem.ecosystem. RhizobiumRhizobium provides plants with nitrogen. provides plants with nitrogen. A few bacteria are used to clean up small oil A few bacteria are used to clean up small oil

spills in the ocean.spills in the ocean.

VaccinationsVaccinations A weakened form of the pathogen A weakened form of the pathogen

(virus/bacteria) is used to (virus/bacteria) is used to stimulate the production of stimulate the production of antibodies.antibodies.

However, bacteria and viruses However, bacteria and viruses have very high reproductive rates, have very high reproductive rates, which result in many mutations.which result in many mutations.

Thus, bacteria and viruses evolve Thus, bacteria and viruses evolve quickly, often requiring a different quickly, often requiring a different vaccine every year.vaccine every year.

http://www.biojobblog.com/vaccination(5).jpg

http://www.biojobblog.com/vaccination%5B1%5D.JPG

There are two types There are two types of vaccines of vaccines (immunities):(immunities):

Active – person is Active – person is injected with the injected with the actual pathogen, actual pathogen, and immune cells and immune cells make their own make their own antibodies against antibodies against the disease, the disease, immunity is immunity is permanentpermanent

Passive – person is Passive – person is injected with injected with antibodies that fight antibodies that fight the disease, but the disease, but immunity is immunity is temporarytemporary

http://www.iavi.org/viewpage.cfm?aid=1682