1. Bacteria are classified by the Gram stain.
Gram positive bacteria appear purple after Gram staining.
Gram negative bacteria appear pink after Gram staining.

3. Gram Positive
Gram positive bacteria have a thick cell wall rich in peptidoglycan
Gram-positive bacteria are important in industry and medicine
Many antibiotics will kill Gram-positive bacteria
Examples include Staphylococcus aureus, Mycobacterium tuberculosis, Bacillus anthracis, Bacillus subtilis

4. Gram Negative
Gram negative bacteria have complex cell walls with less peptidoglycan
Many species of Gram negative bacteria are pathogenic (not all)
Gram-negative bacteria are often tougher to kill, resisting common antibiotics
Examples include Escherichia coli, Salmonella enteritidis, Haemophilus influenzae

5. Bacteria and their energy
Autotrophs
Chemotrophs
Heterotrophs

6. Autotrophs
Make their own energy
Using Solar energy
Eg. Cyanobacteria

7. Chemotrophs
Make own Energy
Using Chemical energy
Eg. Archaebacteria

8. Heterotrophs
Obtain food
By eating
Eg. E-coli

9. Bacteria Respiration Obligate Anaerobes Live without Oxygen
Facultative Anaerobes
Obligate Aerobes
Live without Oxygen
Can live with or without oxygen
Cannot live without oxygen.

10. Symbiosis
Close relationship between to species in which at least one species benefits from the other
Live together for LIFE

11. Parasitism Bacteria exploit the host cell, injuring them
Eg. Mychobacterium tuberculosis

12. Mutualism
Symbiosis in which two of the species live together in such a way that both benefit from the relationship
Eg. E-coli

13. Nitrogen Fixations
Process by which nitrogen in the atmosphere is converted into a form that can be used by living things.

14. Protection
There are a few big ways to protect yourself against pathogens (disease causing agents)
Antibiotics (drugs to kill bacteria)
Antivirals (drugs to treat viruses)
Vaccination (using your body’s own immune system to preemptively guard against attack)

15. Antibiotics
Antibiotics can only be used to treat bacterial infections!
Target specific structures on bacteria to kill them.
First made from a fungus (penicillin), now most are made artificially.
Unfortunately, antibiotic resistance (where the antibiotic doesn’t kill the target bacteria anymore) is becoming a major problem.

16. Antivirals
Antivirals can only be used to treat certain viral infections!
Does not “kill” or disarm the virus permanently; only shortens symptoms by 1-2 days.
Usually only prescribed to patients with life threatening symptoms.
Just like antibiotics, there is evidence of antiviral resistance too!

17. Vaccination
Vaccines can only be used to prevent infections (both viral and bacterial) from leading to disease.
“Trick” your immune system to make antibodies that destroy foreign “bodies” or particles (such as bacteria and viruses). Your body remembers how to make these antibodies when the real thing invades.
Made from a weakened virus, inactivated virus, or by using only part of the virus/bacteria itself

18. VIRUS
Viruses consist of DNA or RNA enclosed in a simple protein shell known as a capsid. General properties of viruses They are very small in size, from m. They contain one kind of nucleic acid (RNA or DNA) as their genome. They are metabolically inert They are obligate intracellular parasites. They are only seen by electron microscope. They are unaffected by antibiotics. They are sensitive to interferon.
Morphology of viruses

19. Morphology of viruses