What is a virus? A virus is… - PowerPoint Presentation

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2. What is a virus?A virus is…A virus (from the Latin virus meaning toxin or poison) is a microscopic organism consisting of genetic material (RNA or DNA) surrounded by a protein, lipid, or glycoprotein coat.

3. Structure of a virusViruses are not cellular genetic elements that use a living cell for their replication and have an extracellular state.Viruses are ultramicroscopic particles containing nucleic acid surrounded by protein, and in some cases, other macromolecular components such as a membrane like envelope.

4. Structure of a virusViruses vary considerably in size and shape. The smallest viruses are about 20 nanometers, while the large viruses measure about 300 nanometers.

5. Structure of a virusSmallpox viruses are among the largest viruses; polio viruses are among the smallest. ( A strand of human DNA is 2.5 nanometers in diameter.)

6. Most common VirusesChickenpox – This infection is caused by the varicella zoster virus. It is highly contagious, being spread through coughing, sneezing, or contact with secretions. The main noticeable symptom is a skin rash. Ebola – Infection with this virus can lead to hypovolemic shock due to coagulation problems caused by the virus. It is spread through body fluids, conjunctive, and also orally. include fever, vomiting, and malaise.Hepatitis B – This virus causes the disease Hepatitis B. This disease infects the liver and can lead to liver cirrhosis and even liver cancer. The virus is transmitted through infected blood or body fluids with infected blood.Hepatitis C – Hepatitis C infects the liver and is caused by the Hepatitis C virus. This virus is transmitted from person-to-person through contaminated blood.Herpes – Herpes is a group of several viruses that infect humans. Diseases caused by the herpes viruses include cold sores, genital herpes, chickenpox, and shingles. Herpes viruses are spread between people by way of body fluids, through the air, and through contaminated objects and surfaces.HIV – Human immunodeficiency virus (HIV) is the virus that causes AIDS. The virus attacks the immune system, which eventually allows other diseases to infect and proliferate in the body. HIV can be spread through blood, semen, breast milk, and vaginal fluid.Measles – The measles virus is the cause of the disease measles. The virus only infects humans and is spread through respiratory secretions. Complications may occur and can include pneumonia, encephalitis, and even death.Mumps – The mumps virus causes the disease mumps in people. The disease is transmitted from person-to-person through respiratory secretions but is generally a self-limiting disease and is not fatal in most circumstances. Rabies – The rabies virus causes a fatal disease in animals and humans. Transmission of the virus often occurs through the saliva of animals.Shingles – This is a skin rash caused by the varicella zoster virus. In children, this virus causes chickenpox. Symptoms of shingles include skin pain and burning and a rash.Smallpox – The variola virus causes smallpox. Symptoms of smallpox can include body aches, fever, vomiting, malaise, and a rash of fluid-filled bumps that cover the body.

7. BacteriophagesBacteriophage- infects bacterial cells.Phages infect bacterial cells and clings onthe bacteria's cell wall.The Bacteriophage will use either of the two cycles, Lytic or Lysogenic.Uses chemical energy of host cell and produces new Bacteriophages and infect other cellsThis is a T4 Bacteriophage.Most CommonEthan Kim

8. BacteriophageThe Lytic CycleLysogenic cycleORThe infected cell in lytic cycle is disintegrated along with the cell's membrane Ethan Kim

9. RetrovirusesRetroviruses: infect cells.Infects the cell by releasing it's genetic code(RNA).The retroviruses RNA is reverse transcribedRNA -> DNA.Ethan Kim

10. RetrovirusEthan Kim

11. AdenovirusAdenovirus: a family of viruses thatcan cause infections in animals.Affect children more than adults(more often or mostly).It injects its core/ nucleic material.Duplicates using host cell genetic material.Structure:Core protein, Knob domain, and fibers (help connect to cell membrane).Ethan Kim

12. Adenovirus Ethan Kim

13. Examples of EachAn example of a Bacteriophage is the Bubonic Plague (Black Death), Bubonic plague infects the lymph system (important component of the immune system).An example of a Retrovirus is AIDS (Acquired Immunodeficiency syndrome), it infects the immune system ( only if it is badly damaged), people can be vulnerable to other infections. An example of a Adenovirus is Pinkeye (Conjunctivitis),Pinkeye infects the conjunctiva (the membrane that covers the eye and the inner surface of the eyelids).Ethan Kim

14. Lytic Cycle

15. Lytic Cycle Steps 1&2The tail of the Bacteriophage attaches on to the Bacterial cell wallThrough the hollow tubes of the tail, the Bacteriophage then injects Phage DNA into the Bacterium

16. Lytic Cycle Steps 3&4Inside the bacterium, the Phage DNA circulates away from the Host's DNAThe Bacteriophage then takes over the Bacterium's metabolism causing for synthesis of the new Bacteriophage's proteins and nucleic acids.

17. Lytic Cycle Steps 5&6The Bacteriophage proteins and nucleic acids come together into complete Bacteriophage particles. In other words, its replicating.Finally, the Bacteriophage enzyme lyses the Bacterium's cell wall, and then releases new Bacteriophage particles that can attack other cells.

18. Lysogenic Cycle

19. Lysogenic CycleStep One: The phage attaches to the cell. Phage-Bacteriophage is a virus that infects and replicates within a bacterium.Step two: The DNA Enters the lysogenic cycle The Cycle of virus reproduction

20. Lysogenic CycleStep three: The new phage DNA and proteins are synthesized into virions Step four: Lysogenic bacteria reproduces normally

21. Lysogenic CycleStep Five: After many cell divisions, the prophage will enter the lytic cycle