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viral reproduction

Discussion in 'MCAT Discussions' started by lady bug, May 14, 2002.

  1. lady bug

    lady bug 7+ Year Member

    578
    1
    Jan 3, 2002
    Which one is more detrimental to the host- lytic cycle or lysogenic cycle?
     
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  3. Green912

    Green912 10+ Year Member

    724
    0
    Jun 11, 2001
    The lytic cycle is where the virus is actually breaking out and causing cell death.
     
  4. Street Philosopher

    Street Philosopher freebird 10+ Year Member

    6,279
    7
    Aug 10, 2000
    ann arbor
    it's debatable.
    one thing that's good about the lysogenic cycle (in the virus' perspective) is that your host doesn't die off immediately. you can assure a high number of viruses before killing off the host and going to a new one.
     
  5. Mr. Z

    Mr. Z Senior Member 7+ Year Member

    451
    0
    Apr 19, 2002
    Philadelphia
    During a lytic cycle, the bacteriophage uses the replicative machinery of the bacterial cell to make many copies of its viral genome and to produce structural proteins of the phage head and tail. After phage DNA genomes are packaged into phage particles, the cell lyses (ruptures), releasing progeny phage capable of infecting other bacteria.

    During a lysogenic cycle, the phage's DNA is inserted into the circular bacterial chromosome. The viral genome remains dormant in the bacterial chromosome, being replicated and passed to progeny bacteria along with host DNA sequences. When an appropriate extracelluar signal (e.g. environmental stress, UV light) impacts the bacterium, the viral plasmid genome is excised from the bacterial chromosome, and the phage initiates a typical lytic cycle.

    So as far as which is more detrimental, the lytic will have a more immediate impact. However, over time it seems they both will eventually destroy the host.
     
  6. Mr. Z

    Mr. Z Senior Member 7+ Year Member

    451
    0
    Apr 19, 2002
    Philadelphia
    Here is a physics question concerning optics...

    When light travels from air to water

    a. it's frequency increases
    b. it's frequency decreases
    c. it's wavelength increases
    d. it's wavelength decreases

    And most importantly, why does the effect occur?
     
  7. Rapid Decomposition

    Rapid Decomposition 10+ Year Member

    410
    0
    Feb 28, 2002
    I think the answer is D. The n of water is greater than the n of air, and since n=c/v, v is slower in water. v=frequency times wavelength, and since the frequency is always constant, the wavelength goes down.
     

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