Bacteria & Viruses

4 Ways to Identify Bacteria 1.Shape CocciBacillusSpirochete

2.Cell Wall Peptidoglycan – in bacteria cell wall Gram (+) Purple Gram (-) Red

3. Movement Flagella Slime Layer None

4. How they get their energy Photoautotroph Chemoautotroph Heterotroph Photoheterotroph

Bacterial Reproduction & Growth Binary Fission Conjugation

Oxygen Needs of Bacteria Facultative Anaerobe Obligate Aerobe Obligate Anaerobe Oxygen at top

Nitrogen Fixation Process where bacteria on plant roots convert nitrogen gas in the air into ammonia Nitrogen is necessary for proteins and nucleic acids Mutualism! Both plant and bacteria benefit

Human uses for bacteria

Pathogens – Bacteria that cause disease Two Ways Bacteria Cause Disease Produce Toxins (Food poisoning) Damage Tissue

Controlling Bacterial Growth Antibiotics – Slows growth; does not kill bacteria Disinfectants – Chemical that kills bacteria Sterilization – Heat, pressure, gas that kills bacteria Refrigeration – Slows growth; does not kill bacteria Canning – High heat to kill bacteria Chemical Treatments – Preservatives in food; slows growth; does not kill

Virus – Obligate Parasite – Must have a host to survive and multiply DNA or RNA Capsid

Lytic Cycle of a Virus

Lysogenic Cycle of a Virus

How Vaccines Work

Oncogenic Viruses Disrupt cyclins that regulate cell growth

Retroviruses Have RNA which needs Reverse Transcriptase to convert into DNA and then added into host DNA for replication of virus

Prions – Infectious Proteins when eaten target specific tissues such as the brain Mad Cow Disease Scrapies in Sheep