What do the following have in common?

Can you Identify the picture below?

Characteristics of Life

• Made of Cells

• Reproduce

• Metabolize (energy)

• Grow

• Respiration

• Respond to environmental changes

• How can you prevent the spread of disease? (3)

• How could know if an individual is infected with a pathogen? explain

• What do we know about viruses?

• Why are viruses not classified in any of the 6 kingdoms?– Have to have a host in order to reproduce– Don’t have independent metabolism– Don’t grow– NOT CELLULAR

Virus Characteristics

• Do not use energy

• Do not reproduce

• Do not grow

• Do not respond to environment

• Are not cellular

• Obligate intracellular parasites

Why do some scientists consider viruses to be “alive?”

•Contain all organic compounds– Carbs, proteins, lipids and nucleic acids– (same chemicals as a living organism)

•Under right conditions, being inside of a host cell, they can carry out life process.

•They replicate (NOT reproduction)

Obligate intracellular parasites

• Commit inside a cell and uses the cell as a host to function

VIRUSES

EBOLA

RABIESFLU

BACTERIOPHAGE

Organic?

Virus Defined

• Infectious pathogen that infects living cells, replicates inside cells making new viral particles causing disease

• DNA encased in a protein/carbohydrate coat

Types of Viruses

Polyhedral enveloped

helical

Bacteriaphages attacking a bacterial cell

Types of Viral Diseases

• Rabies• Ebola (hemorrhagic)• Flu (influenza)• HIV• Hepatitis

WE can only treat symptoms of viruses!!!

We can not CURE!!

• Chicken pox

• Measles

• Rubella

• Mumps

• Smallpox

• Polio

• Yellow fever

• Parvovirus (canine)

• Dengue fever (hemorrhagic)

• Herpes

• How a Virus invades your cells

– http://www.youtube.com/watch?NR=1&v=Rpj0emEGShQ&feature=fvwp

• Lysogenic: http://www.youtube.com/watch?v=_J9-xKitsd0

• http://biology.about.com/gi/o.htm?zi=1/XJ&zTi=1&sdn=biology&cdn=education&tm=2&gps=342_220_1020_583&f=00&tt=2&bt=0&bts=1&st=14&zu=http%3A//student.ccbcmd.edu/courses/bio141/lecguide/unit3/viruses/adlyt.html

Virus Hunters

1. What factors influenced the spread of disease?

2. What helped to prevent the spread of disease.

3. Discuss one virus you learned from the video and describe symptoms, treatment, or interesting fact of the virus.

Vaccinations• Stimulates Active immunity

• Injection of portion of virus (virus particles) that stimulate an immune response….causes body to make antibodies against particular diseases

http://health.howstuffworks.com/vaccine.htm

Immune Responses

• Passive– Formation of antibodies– To the fetus thru the placenta, thru breastmilk, thru

administration of plasma (artificial)

• Active– Formation of your own antibodies– Vaccinations – by contracting an infectious disease by exposure of

an antigen

1

2

3

4

• Lysogenic Infection: • Similar to lytic infection however important

differences exist

• Instead of immediately replicating, viral DNA incorporates itself into the host cell's DNA.

• Will remain dormant for significant amounts of time.

• Give certain conditions (stress), the virus will enter it's lytic phase similar to a normal lytic infection

Prions

Proteinaceous infectious particles

What are they?

• Proteinaceous infectious particles– Infect brain or other

neural tissue– Untreatable and fatal– β sheets are thought to

lead to amyloid aggregation.

http://learn.genetics.utah.edu/content/begin/dna/prions/

Bovine Spongiform Encephalopathy

• Also known as "Mad Cow Disease"

• Infected animals act strangely and can be aggressive

• Spread rapidly through Britain by rendering infected animals into cattle feed

Scrapie

• Recognized in sheep and goats for more than 250 years

• 1982 1st identified as a prion disease

Kuru“laughing death”

• New Guinea• Muscle weakness, loss of

coordination, tremors, inappropriate episodes of laughter or crying

• Was the most common death of women

• Mortuary feasting– Forbidden by Australian

government in 1950’s

Viroid

• Single strand of RNA (THAT’S IT!!)

• Infects plants• 1 viroid disease has

killed over 10 million coconut palms in the Philippines