Viruses and Bacteria
Mr. Fox 7th Grade Science
Virus
• A small non-living particle that makes its way inside a cell and the nucleus.
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Why are Viruses Non-Living
• They are not cells.–Do not use oxygen to make energy
–Do not take in food–Do not produce proteins
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Infection
• Parasite – an organism that feeds on other organisms and causes harm.
• Host – a living thing that provides a source of food (or living space) for a virus or living thing.
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Task
• In your notes with a partner: Explain how viruses multiply and cause harm.
• Go to Page 54 and answer questions 2 and 4.
• Name some common viruses. 5
Common Viruses
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Ebola
Rhino Virus
Polio Virus
Bacteria
• The most numerous living things. All bacteria are prokaryotic.–They do not have a nucleus
–Most bacteria have ribosomes
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Shapes of Bacteria
• Spherical Cocci
• Rod ShapedBacilli
• Spiral Shaped Spirilla
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Reproduction
• Reproduce by binary fission. (asexual)
– Each new cell is exact to the parent
• Some bacteria exchange DNA in a form of sexual reproduction.
– No new bacteria are formed though
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Feeding Habits
• This is what makes them so numerous• Some are autotrophs and they make their
own food. • Some are heterotrophs and eat almost
ANYTHING! • Some need oxygen while others would die
in oxygen’s presence.
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Task• In your NOTES!
Many infectious diseases are caused by viruses or bacteria. What are some of the diseases you have had that were caused by a virus or bacteria. (hint later)
What is the best way to protect yourself against most viral or bacterial diseases?
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