Viruses and Bacteria Mr. Fox 7 th Grade Science

Virus A small non-living particle that makes its way inside a cell and the nucleus. 2

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 3

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. 4

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 6 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 7

Shapes of Bacteria Spherical Cocci Rod Shaped Bacilli Spiral Shaped Spirilla 8

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 9

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. 10

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? 11