Microbiology lecture 5

  1. Bacteria VS Virus
    • Bacteria
    • free living, living cells, DNA is their genetic information
    • Viruses
    • dependent on host ribosomes, is not a cell or living, genetic information can be either DNA or RNA
  2. Viral Structure (5 parts)
    • Genome
    • Capsid
    • Envelope
    • Nucleocapsid
    • Viral Attachment Proteins (VAP)
  3. Viral Attachment Proteins
    Surface structure of capsid & envelope that mediate interaction of virus with target cell
  4. 3 Types of viral infections
    • •Viruses can lyse cell (kills cell)
    • •Viruses can be maintained in body without symptoms (until host is immunocompromised)
    • •Viruses can transform cells
  5. RNA Virus Classification:

    + strand viruses
    • Acts as its own mRNA– Called “infectiousnucleic acids”
    • Bind to ribosomes and begin to codefor proteins

    • RNA-dependent RNA Polymerase first – allows it to make complementary strand (- strand)
    • + strand is infectious strand
    • Ex: Poliovirus, common cold
  6. RNA Virus Classification:

    - (negative) strand virus
    All are enveloped viruses

    • Needs to make its mRNA (can’t act as its own message)
    • Carries its own RNA Polymerase with it
    • Takes longer to become active than + strand viruses
    • non infectious
    • Ex: Rabies virus
  7. RNA Virus Classification:

    • has a single strand of RNA
    • carries a reverse transcriptase with it
    • stays in host genome indefinately or comes out to make viral RNA
Card Set
Microbiology lecture 5