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Viruses, HIV, & AIDS

Viruses, HIV, & AIDS. Virus Introduction. Viruses are not living things. Traits of Living Things. Viruses consist of nucleic acids & proteins. Living things consist of cells Cells are made up of complex compounds: proteins, lipids, carbohydrates, & nucleic acids Living things reproduce

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Viruses, HIV, & AIDS

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  1. Viruses, HIV, & AIDS

  2. Virus Introduction Viruses are not living things Traits of Living Things Viruses consist of nucleic acids & proteins. • Living things consist of cells • Cells are made up of complex compounds: proteins, lipids, carbohydrates, & nucleic acids • Living things reproduce • Living things grow & develop • Living things convert energy & carry out metabolism Viruses replicate, but need a host cell in order to do so. Viruses don’t grow, develop, or carry out respiration Viruses are not cells (no membrane or cytoplasm)

  3. Viral Structure Viruses may have spikes Viruses have a protein coat called a capsid Viruses may have an envelope that consists of part of cell membranes The capsid encases nucleic acid (DNA or RNA) Viruses are very small (< 1mm) Adenoid Virus

  4. Viral Replication A Virus Must Enter a Host Cell to Replicate Virus binds to membrane of host cell 1. Attachment: Virus injects its nucleic acid into the host cell 2. Entry: Host cell makes viral DNA & viral proteins 3. Replication: New viruses assembled from proteins & nucleic acids 4. Assembly: Host cell releases new viruses 5. Release:

  5. Influenza Colds Mono- nucleosis West Nile Disease Hepatitis Polio Small Pox Mumps Rabies Measles Chicken Pox Viral Diseases

  6. Polio Virus Rotavirus Ebola Virus Hepatitis B Virus Rabies Virus Herpes Virus

  7. Influenza Virus Tobacco Mosaic Virus Small Pox Virus Adenoid Virus Pneumovirus Bacteriophage

  8. Virus Review Are Viruses Living? No, viruses are technically not considered living things. Why? • Viruses do not carryout metabolic reactions like respiration or photosynthesis. They don’t convert energy • Viruses are unable to reproduce or replicate on their own And Most Importantly... VIRUSES ARE NOT CELLS…THEY DO NOT HAVE A MEMBRANE & CYTOPLASM

  9. Virus Review What Is a Virus? • Viruses are non-living particles that consist of fragments of cells (protein & nucleic acid) • Viruses are less than 1 mm in size • Viruses are able to replicate, but need to do so in a “host cell”

  10. HIV & AIDS

  11. HIV Basics HIV stands for Human Immunodificiency Virus HIV is a Retrovirus HIV targets white blood cells HIV infection results in AIDS

  12. Viral DNA Cell's DNA Retroviruses Contain RNA for a nucleic acid Revearse Transcriptase Enzyme produces DNA from RNA DNA integrated in host cell's DNA Viral RNA

  13. Sugar / Protein Spike in Envelope Called a Glycoprotien (gp 120) Lipid Envelope from membrane of infected cells Reverse Transcriptase enzyme attached to RNA Matrix Protein Capsid (P 17 & P 24) surrounds RNA 100 nm diameter HIV Structure

  14. HIV Replication HIV Binds to Immune Cells: gp 120 locks to cell’s CD4 protein Attachment: • HIV injects RNA into CD4 cell. • Reverse transcriptase produces DNA from RNA. • Viral DNA embeds in cell’s DNA in nucleus Entry: Cell’s DNA Produces viral RNA and proteins Replication: Viral proteins & RNA assemble into new virus at the membrane Assembly: Virus buds at membrane. Part of CD4 cell membrane becomes viral envelop. Release:

  15. HIV infects cells that have CD4 Proteins Helper T Cells Macrophages CD4 Protein CD4 Cells Include...

  16. Disorders of the Immune System: AIDS Acquired Immune Deficiency Syndrome When the immune system is lacking one or more of its components, the result is an immunodeficiency disorder. AIDS is an immunodeficiency disorder caused by a virus that destroys helper T cells and that is harbored in macrophages as well as helper (T4) T cells. The AIDS virus splices its DNA into the DNA of the cell it infects; the cell is thereafter directed to churn out new viruses.

  17. Progression of AIDS HIV infects the vulnerable CD4 cells and replicates at a high rate within these cells. As the number of infected cells increases, the destruction of the immune system progresses. The rate of viral replication in productively infected CD4 cells is extremely high (one billion viral particles are produced every day).

  18. Progression of AIDS The immune system controls the infection by producing vast numbers of T helper cells. The battle between the viral infection and the cells of the immune system continues. Eventually the virus' ability to damage the immune system exceeds the body's capacity to fight HIV. Normal Immunity Onset of AIDS 500 - 1500 CD4 Cells per mm3 of Blood < 200 CD4 Cells per mm3 of Blood

  19. The End HIV / AIDS Summary AIDS is caused by HIV infection HIV is a retrovirus HIV infects helper T cells (CD4 cells) HIV infection compromises the immune response AIDS results in death

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