VirusesViruses

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 it’s not!but it’s not!

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

reproduce themselvesreproduce themselves They have no metabolism outside the cellThey have no metabolism outside the cell They do not have cell parts (e.g., nucleus, They do not have cell parts (e.g., nucleus,

mitochondria)mitochondria) They comprise only a nucleic acid (DNA or RNA) They comprise only a nucleic acid (DNA or RNA)

inside a protein capsuleinside 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

Complete the diagram!

Virus reproductionVirus 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 The viral nucleic acid commands the cell to make

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

new viruses.new viruses.

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

RetrovirusesRetroviruses

No, they aren’t from the 70sNo, they aren’t from the 70s These viruses store their genetic information These viruses store their genetic information

as RNAas RNA Example: HIVExample: HIV

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

Archaea and BacteriaArchaea and Bacteria

Archaea v. BacteriaArchaea v. Bacteria

Bacteria have peptidoglycan Bacteria have peptidoglycan and certain specialized lipids in and certain specialized lipids in their cells walls that are not their cells walls that are not present in Archaeapresent in Archaea

Bacteria live in the same Bacteria live in the same environment as humans, some environment as humans, some are anaerobic)are anaerobic)

Archaea live in EXTREME Archaea live in EXTREME conditions (high pressure/ conditions (high pressure/ temperature, deep sea vents)temperature, deep sea vents)

Most are anaerobic!Most are anaerobic!

Kingdom Bacteria…your Kingdom Bacteria…your friendly neighborhood bacteriafriendly neighborhood bacteria

Bacteria are living, unicellular Bacteria are living, unicellular prokaryotes.prokaryotes.

Heterotroph or autotroph (most Heterotroph or autotroph (most use chemosynthesis).use chemosynthesis).

Bacteria are classified based on Bacteria are classified based on their shape, type of cell wall, their shape, type of cell wall, and movement.and movement.

Bacteria have three basic Bacteria have three basic shapes: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 Bacteria

Cell membrane

Cell wall

Ribosomes

DNA

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

Complete the

diagram!

Bacteria reproductionBacteria reproductionBacteria reproduce asexually:Bacteria reproduce asexually: Binary fissionBinary fission – a bacteria – a bacteria

doubles in size; copies its DNA doubles in size; copies its DNA and divides, producing two and divides, producing two identical cells. identical cells.

Spore formationSpore formation – in – in unfavorable conditions (lack of unfavorable conditions (lack of food, water) bacteria form a food, water) bacteria form a capsule that encloses its DNA capsule that encloses its DNA and part of its cytoplasm and part of its cytoplasm

When conditions are better, the When conditions are better, the spore germinates and grows. spore germinates and grows.

They’re not all bad…They’re not all bad… Bacteria are most widely known Bacteria are most widely known

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

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

in our ecosystem.in our ecosystem. RhizobiumRhizobium provides plants with provides plants with

nitrogen.nitrogen. A few bacteria are used to clean A few bacteria are used to clean

up small oil spills in the ocean.up small oil spills in the ocean.

VaccinesVaccines

A weakened form of the A weakened form of the pathogen (virus/bacteria) is used pathogen (virus/bacteria) is used to stimulate the production of to stimulate the production of antibodies.antibodies.

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

Thus, bacteria and viruses Thus, bacteria and viruses evolve quickly, often requiring a evolve quickly, often requiring a different vaccine every year.different 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 immunity – Active immunity – person is injected person is injected with the actual with the actual pathogen, and pathogen, and immune cells make immune cells make their own antibodies their own antibodies against the disease, against the disease, immunity is immunity is permanentpermanent

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

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