1. Bacteria and Viruses
p. 137 in ILL
6/1/12

2. Bacteria Characteristics Oldest forms of life on Earth
Single- celled organisms
Prokaryotic—no nucleus
Contain DNA
Most are consumers and eat other organisms for food, many are decomposers, some live in or on the body of other organisms, and some are producers

3. Bacteria Shape Most have rigid cell walls that give shape
Bacteria come in one of 3 shapes rod (bacilli), sphere (cocci), or spiral (spirilla)

4. Bacteria Reproduction
Bacteria can reproduce quickly by a process called binary fission.
Their reproduction is slowed down by cold (refrigeration or freezing), heat (pasteurization and sterilization), and salting.

5. Bacteria Role in the World Good for the Environment Nitrogen cycle
Decomposition
Good for the People
In food…cheese, yogurt, buttermilk, sour cream, etc.
Medicines…fighting other bacteria, antibiotics, insulin
Genetic Engineering…change genes of bacteria to make insecticides, cleansers, adhesives, etc

6. Bacteria Role in the World continued…
Harmful Bacteria (infectious disease)
Pathogenic (disease causing)…tuberculosis, Lyme disease, MRSA, leprosy, strep, etc.
Can be treated with antibiotics--medicines taken by an infected person to kill the bacteria in the body (penicillin, amoxicillin, tetracycline)
Some antibiotics have been overprescribed and by natural selection, bacteria have become resistant (can’t be killed) to certain medications. This is known as antibiotic resistance.

7. Bacteria

8. Bacteria Role in the World continued…
Harmful Bacteria (Infectious disease)
Can also be treated with vaccinations—substances that stimulate the body to produce chemicals (antibodies) that destroy familiar invaders

9. Viruses Characteristics/Reproduction
Viruses are neither living nor dead
They are non-cellular
Viruses are significantly smaller than bacteria (5 billion virus particles can fit in a single drop of blood)
Do not use energy, need food or create waste
Contain DNA and protein coat
Can only reproduce inside a host cell which it often destroys
Can add their genetic material to a host cell that stays inactive for a very long time

10. Viruses
Shapes
Four main shapes: crystals, spheres, cylinders and spacecraft

11. Viruses Role in the World Good for the Environment Good for People
Population control…limiting factor
Good for People
Can be manipulated to create medicines and treat some diseases (very new technology)

12. Viruses Role in the World continued…
Harmful Viruses (infectious disease)
Pathogenic (disease causing)…HIV, Hepatitis A, B, & C, Chicken Pox, Small Pox, Ebola, Rabies, Swine Flu, Influenza, Common Cold, etc.
Cannot be cured with medications…only symptoms can be treated
Many can be prevented with vaccinations (like bacterial infections)

13. Viruses