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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