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VIRUSES ARE NOT ALIVE BUT AFFECT LIVING THINGS PowerPoint Presentation
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VIRUSES ARE NOT ALIVE BUT AFFECT LIVING THINGS

VIRUSES ARE NOT ALIVE BUT AFFECT LIVING THINGS

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VIRUSES ARE NOT ALIVE BUT AFFECT LIVING THINGS

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  1. VIRUSES ARE NOT ALIVE BUT AFFECT LIVING THINGS

  2. VIRUSES SHARE SOME CHARACTERISTICS WITH LIVING THINGS • VIRUSES MULTIPLY INSIDE LIVING CELLS • VIRUSES MAY HARM HOST CELLS

  3. VIRUSES • VIRUS means poison; much smaller than bacteria, can’t even be “filtered” out of a liquid like bacteria can be. • Viruses have genetic material inside of a protective protein coat called a CAPSID. • They come in many shapes & sizes, but all have a CAPSID and GENETIC MATERIAL. • VIRUSES must use a host cell to reproduce (by making genetic material & capsids). • Viruses do not grow & don’t respond to changes in the environment, so they are not living organisms

  4. Viruses Multiply inside Living Cells • Viruses use HOST CELLS to make copies of themselves. A bacteriophage (means bacteria eater) is used to show the process. • ATTACHMENT: virus attaches to cell • INJECTION: injects its DNA inside • PRODUCTION: uses cell’s machinery to copy the viral DNA and capsids • ASSEMBLY: viral DNA forces infected cell to assemble new viruses • RELEASE: cell bursts open, releasing 100+ new viruses to infect other cells. • Viruses have proteins on surface that look like proteins the host cell normally needs to fool it & “dock” onto sites of cell membrane

  5. Viruses May Harm Host Cells • Virus uses cell’s material, energy , and processes to reproduce often bursting out & destroying the host cell. (some just hide in cell or just make 1 virus at a time & not be as harmful) • About 25 million people died of influenza virus in outbreak after WWI. • Plant viruses can stunt growth & kill plants • Plant, animals, bacteria & all other living things can be infected by viruses. • Scientists can use viruses to insert pieces of genetic material into living cells. (like a marine organisms DNA into other tissue causing it to glow so can study it better)