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Viruses (emerging viruses; suddenly apparent (Possible explaination…

- - - - especially RNA common mutations
        
        viral RNA polymer-ases do not proofread and correct errors in replicating their RNA genomes
- - - - Smallest viruses can have 3 genes in genome, largest has 2,000
        
        In comparison bacteria has 200 genes through a few thousands
      - Genome organized linear or circular molecule of nucleic acid
    - - RNA genome
        
        Ribosomes bound to the endoplasmic reticulum (ER) of the host
        
        Makes protein then adds sugar
        
        Embodies membrane to be transported to the surface
        
        new viral capsids are wrapped in membrane as they bud from the cell.
        
        Able to infect new cells
        
        1 more item...
        
        3 types of single stranded
        
        IV
        
        Retrovirus
        
        Reverse transcript
        
        RNA to DNA (backwards)
        
        3 more items...
        
        VI
        
        mRNA and can be translated into viral protein immediately after infection
        
        V
        
        Template for mRNA
        
        mRNA transcription require RNA---> RNA synthesis.
        
        Capsid used for the process
        
        Enzyme uses has the viral information
      - DNA genome
        
        combina-tion of viral and cellular enzymes to replicate and transcribe their DNA
  - - - Rod viruses commonly called; helical viruse
      - The shape and structure help to infect the host.
        
        For example; membranous envelope surrounds the capsids of influenza viruses and many other viruses found in animals
    - - elongated icosahedral heads enclosing their DNA
  - - - Through the envelope
    - - Vaccine; pathogen is inserted to build up a stronger immune system to prepare for the virus
        
        Prevents diseases
      - Antibacterials; useless against viruses
        
        eukaryotic or virally encoded enzymes.
- - - - After cycle produce more virues
        
        After can damage or destroy host cells
      - 1st. The virus enters the cell and is uncoated,releasing viral DNA and capsid proteins.
        
        2nd, Host enzymesreplicate the viralgenome.
        
        3rd; Meanwhile, hostenzymes transcribe theviral genome into viralmRNA, which hostribosomes use to makemore capsid proteins.
        
        Viral genomesand capsid proteinsself-assemble intonew virus particles,which exit the cell
    - - lysogenic cycle
        
        Replication without destroying host cell
        
        Phages coexist is called lysogeny.
      - lytic cycle
        
        Death of host cell
        
        A few can destroy entire bacteria population in a few hours
        
        last stage of infection, during which the bacterium lyses (breaks open) and releases the phages that were produced within the cell.
        
        Phages which replicate through this cycle are called virulent phage
      - both cycles
        
        Phages which replicate in both cycles are called temperate phages (lambda)
        
        Prophage; when integrated into a chromosome
        
        lysogenic; propage are able to become active and reproduce to kill host cells (when temperate are made to exit)
        
        Provoked by chemicals or high radiation
        
        During this time viral protein that prevents transcription,
        
        Expression of genes alter host's phenotype
      - bacteria still exists b/c through natural selection
        
        surface Protein not recognized by virus
        
        Restriction enzyme; restrict a phage’s ability to replicate
        
        CRISPR-Cas system
        
        DNA of the invading phage is integrated into the genome between two repeat sequences.
        
        These nucleases, called Cas (CRISPR-associated) proteins, can identify and cut phage DNA,
- - - - invading virus must get past the plant’s outer protective layer of cells
- - - - Act very slow; prevents to be identified, allows many more infections to happen
      - virtually indestruc-tible; they are not destroyed or deactivated by heating to nor-mal cooking temperatures.
    - - then aggregate into a complex that can convert other normal proteins to prions, which join the chain
- - - - Wendell Stanley crystal-lized the infectious particle
        
        Many viruses were seen by an electron microscope