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What we know about Bacteria…

What we know about Bacteria…. Prokaryotic: No Nucleus & no membrane bound organelles Unicellular Can be good or bad 2 Kingdoms LIVING. Viruses. Doesn’t belong to any kingdom -It’s not a plant or an animal. -It’s not a fungi, protist, or bacteria. WHAT IS A VIRUS?.

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What we know about Bacteria…

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  1. What we know about Bacteria… • Prokaryotic: No Nucleus & no membrane bound organelles • Unicellular • Can be good or bad • 2 Kingdoms • LIVING

  2. Viruses Doesn’t belong to any kingdom -It’s not a plant or an animal. -It’s not a fungi, protist, or bacteria. WHAT IS A VIRUS?

  3. The sole purpose of a virus is to duplicate and create more viruses.

  4. A virus is an infectious agent made up of nucleic acid (DNA or RNA) wrapped in a protein coat called a capsid. Viruses have no nucleus, no organelles, no cytoplasm or cell membrane—Non-cellular This is why it does NOT belong to any kingdom. vs

  5. Size of a virus… • The tiniest viruses are 20 nm in diameter. (smaller than a ribosome) • The smallest have 4 genes and largest have several hundred.

  6. Without a host, viruses can lie dormant indefinitely.

  7. Viruses have either DNA or RNA but NOT both. • Viruses are parasites—an organism that depends entirely upon another living organism (a host) for its existence in such a way that it harms that organism. HIV Infected Cell (This is the reason why HIV is so incurable.) A flea is a parasite to a dog and is harmful to the dog.

  8. Bacteriophage—viruses that infect bacteria Capsid(protein coat) • inside contains either • RNA or DNA DNA or RNA Surface Marker 2. Flu (influenza), HIV Capsid(protein coat)

  9. Capsid Nucleic Acid Bacteriophage—a virus that infects bacteria (bacteria is the host)

  10. Certain viruses can only attack certain cell types. They are said to be specific. Example: The rabies virus only attacks brain or nervous cells. Surface Markers Virus Receptor Sites It’s like the pieces of a puzzle. The ends have to match up so only certain pieces fit. “Lock & Key” Cell

  11. A virus recognizes cells it can infect by matching its surface marker with a receptor site on a cell. Virus Surface Markers Cell Receptor Sites

  12. Viruses are “host” specific • –Plant viruses Tobacco Mosaic Virus • –Animal viruses Rabies Virus HIV/AIDS • Swine flu can infect swine or humans • –Bacterial viruses These are called bacteriophages

  13. Each type is independent of the other • EX: A virus targets host cells in the stomach. If a person inhaled this type of virus they would not be harmed. Rotavirus: Children get a vaccine (since 2006) d/t Severe sickness & dehydration This can cause.

  14. Chicken Pox (varicella-zoster virus) • Respiratory virus – enters through the respiratory track • After it resolves, it retreats into spinal sensory nerve tissue & goes dormant. • You will still have the virus & it can reactivate into shingles (adult form)

  15. Importance: *Harmful Causes disease—pathogenic Disease producing agent—pathogen Human Diseases: Warts, common cold, Influenza (flu), Smallpox, Ebola, Herpes, AIDS, Chicken pox, Rabies Viruses disrupt the body’s normal equilibrium/balance Some Viruses can be prevented with vaccines, but NOT treated with antibiotics. (antibiotics treat bacteria)

  16. E. Coli is a bacterium found in the gut of all warm-blooded animals & most is harmless!! • A particular toxin (Shiga toxin) found in bacteriophages can cause dreadful effects. • So, the bacterium must first be infected by a bacteriophage coding for the Shiga toxin in order to produce the toxin itself.

  17. Herpes Virus • There are 8 different types of herpes. • Once you are infected – you have it for life (dormancy) • EX: Warts, fever blisters, Epstein-Barr (mono), Chicken pox

  18. Beneficial viruses: • Genetic Engineering—harmless virus carries good genes into cells.(Bacteria are also used for Genetic Engineering)

  19. Virus Living Cell RNA or DNA core (center), protein coat (capsid) Cell membrane, cytoplasm, genetic material, organelles Structure Copies itself only inside host cell--REPLICATION Asexual or Sexual Reproduction DNA and RNA Genetic Material DNA or RNA Growth and Development NO YES—Multicellular Organisms Obtain and Use Energy NO YES Response to Environment YES NO Change over time NO YES

  20. How many characteristics of life do viruses possess? ONE *Genetic Material Are viruses living? NO

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