Viruses Bacteria and the Immune System

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Viruses Bacteria and the Immune System

• Shir Kochinski
• Leila Chitayat
• Jock Fullmer
• Elle Masri

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What is a Virus?

• A virus is a particle of nucleic acid, protein,
  and in some cases lipids.
• Viruses can only reproduce by infecting living
  cells.
• A typical virus is composed of a core of DNA or
  RNA surrounded by a protein coat

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Retrovirus

• A retrovirus infect cells with RNA. The RNA is
  then copied into DNA by reverse transcriptase
  which is inserted as a prophage.

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Lytic

• A lytic infection is the process in which a virus
  enters a cell, makes a copy of itself, and causes
  the cell to burst.
• An example of this is Ebola.

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Lysogenic

• A lysogenic infection is the process by which a
  virus embeds its DNA into the DNA of the host
  cell and is replicated along the host cells DNA.
• An example of this is HIV

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Gram Staining

• Gram staining is used to tell cell walls that are
  found in the eubacteria apart.
• Gram positive bacteria has thick peptidoglycan
  walls that retain dark color of violet or purple.
• Positive purple
• Gram negative bacteria has much thinner walls
  inside a lipid layer.
• Negative pink

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Bacterial Shapes

• Bacilli- rod shaped
• Cocci- spherical shaped
• Spirilla- spiral shaped

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White Blood Cells Lymphocytes and Phagocytes

• Lymphocyte produces antibodies that help destroy
  pathogens. Lymph nodes contain lymphocytes
  (T-cells and B-cells).
• Phagocytes an example of this is a macrophage.
  They contain the enzyme lysozyme, which destroys
  disease.

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Inflammation

• The first line of defense is your skin which
  secretes mucus, sweat, oil, saliva, etc.
• The second line of defense is your inflammatory
  response
• 1. histamine is released which causes blood
  vessels to dilate causing more blood flow to that
  area
• 2. the dilation of capillaries causes
  phagocytes to be released
• 3. phagocytes engulf (surround) the bacteria
• 4. platelets move out of the capillary to seal
  the wounded area

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Antibodies vs. Antigens

• Antibody is a protein that helps destroy
  pathogens.
• An antigen are the protein markers on the cell
  membrane which triggers an immune response.

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Interferon and Prion

• An interferon is one of a group of proteins that
  helps cells resist viral infections.
• A prion is an infectious particle made up of
  protein rather than RNA and DNA. An example of a
  prion is mad cow disease.