Ms. Stroup 8th Grade Science Microbiology Viruses and Bacteria Ms. Stroup 8th Grade Science Microbiology

Warm-Up Pretend you went to a foreign country where people knew nothing about infectious diseases. You notice people are infected with influenza. Q)How would you explain to someone what the flu is, how they got it, and what it is doing to their body? (Only write the question)

Viruses

Viruses Viruses are NOT classified as organisms because they are NOT free-living cells They need a host cell to live and reproduce They are composed of nucleic acid (DNA or RNA) and a protein coat.

How viruses make you sick.. Viruses invade healthy cells and use the enzymes and organelles of the host cell to make more viruses. This usually kills the host cell in the process

Viral Replication- Lytic Cycle The virus attaches itself to the cell membrane of a host cell. The virus (or its genetic material) penetrates the cell. The enzymes in the host cell uncoats the virus’ capsid. The virus’ genetic material is released into the host cell and begins to make copies in the cells nucleus. New genetic material is enclosed in a new capsid, and a copy of the virus is released out of the cell membrane…ready to invade a new healthy cell.

Viral Transmission Human Contact or insect bite Viral diseases are the most widespread illness in humans. Diseases can range from being mild like the common cold to sever and fatal diseases like cancer or HIV/AIDS.

Prevention/Treatment Vaccines Anti-viral drugs (stop virus from reproducing)

Influenza Pandemics!!! Occur when a new subtype of a virus arises Humans have no or little immunity to it so everyone is at risk Causes serious illnesses worldwide, sometimes in only 6-9 months

Influenza Pandemics!!! Spanish influenza killed 40-50 million people in 1918 Asian influenza killed 2 million people in 1957 Hong Kong influenza killed 1 million people in 1968

Bacteria

Bacteria Facts Prokaryotic, single-celled organisms Can live in a variety of places With oxygen Without oxygen Extreme heat Extreme cold Below and on\Earth’s surface Existed for billions of years!

Bacteria Shapes Cocci are Spherical Bacilli and rod shaped Spirilla and spirochetes are spiral shaped

How Bacteria Reproduce Binary Fission A form of asexual reproduction. The genetic material duplicates and the cell divides into two identical cells. Bacteria can grow and divide extremely rapidly!

How Bacteria Can Cause a Disease Prevent the host tissue from working properly Produce toxins which can destroy the host tissue

Bacteria is not always harmful! Beneficial Harmful Decompose trash in landfills Digest food Produce vaccines Preparation of foods Yogurt cheese Bacteria can cause many illnesses Strep-throat Tuberculosis Pertussis Cholera Anthrax Leprosy Meningitis

Treatment Antibiotics Antibiotic resistance: Because we have overused antibiotics, mutant bacteria can survive antibiotic treatments and give rise to resist treatment.

What diseases can you get from animals or insects? Ticks = Lyme disease Mosquitos = West Nile/ Malaria/ yellow fever Dogs = Rabies/Ringworm/hookworm/roundworm/ Tapeworms…and many more Reptiles = Salmonella Cat = Toxoplasmosis/ tapeworms