Ch. 19

 Eubacteria ◦ Largest kingdom of living things ◦ Live everywhere ◦ Cell wall contains peptidoglycan  Archaebacteria ◦ Cell wall lacks peptidoglycan ◦ DNA sequences more similar to eukaryotes ◦ Live in extreme environments

 Shapes ◦ Rod (bacilli) ◦ Spiral (spirilla) ◦ Spherical (cocci)

 Cell walls ◦ Gram-positive stained have peptidoglycan call walls (violet) ◦ Gram-negative lack peptidoglycan (red)  Movement ◦ Variety of ways….

 Heterotrophs ◦ Chemoheterotrophs and photoheterotrophs  majority  Autotrophs ◦ Photoautotrophs  Cyanobacteria ◦ Chemoautotrophs

 Obligate aerobes ◦ Require oxygen all the time; aerobic respiration  Mycobacterium tuberculosis  Obligate anaerobes ◦ Killed by oxygen; anaerobic respiration  Clostridium botulinum  Facultative anaerobes ◦ Can survive with or without oxygen; both types of respiration  Eschericia coli

 Binary fission ◦ Mitotic; asexual  Conjugation ◦ Gene swapping; sexual  Sporulation ◦ When conditions become unfavorable DNA and a little cytoplasm is enclosed in an endospore

 Decomposers  Nitrogen fixers  Food industry  Mining  Cleaning oil spills  Pharmaceuticals  Oxy Clean

 Bits of DNA or RNA surrounded by a protein coat. That’s it. ◦ They come in a variety of shapes and sizes ◦ They must infect a host cell to reproduce. ◦ Bacteriophages are viruses that infect bacteria.

 Viruses enter a host cell and use the cell’s machinery to reproduce. ◦ In lytic infections the virus reproduces immediately until the cell bursts. ◦ In lysogenic infections the viral DNA is incorporated into the host’s DNA as prophage and may remain dormant for a period of time until reproduction begins.

 Contain RNA instead of DNA ◦ After infecting a cell the RNA is copied in reverse to make DNA which is then incorporated into the host cell’s genome as prophage. ◦ RNA viruses mutate frequently.  Rhino virus (colds)  HIV

Are viruses alive?

 Bacteria and viruses can act a pathogens – disease causing agents (pathos = disease; gen = generating). ◦ Louis Pasteur helped formulate the germ theory of disease. ◦ Bacteria cause disease by either using cells for food or by releasing toxins (poisons) that are harmful.

 Sterilization with heat  Disinfectants  Cold storage  Vacuum packing  Nitrogen/inert gases

 Some target the cell wall of bacteria and others disrupt protein synthesis. ◦ Antibiotics are specific to the type of bacteria they act upon.

 Can’t be treated with antibiotics! They don’t have a cell wall or make proteins… ◦ Best treatment is prevention; once infected it has to run its course. Symptoms may be treated.

 Vaccines provide some protection and immunity to bacterial and viral diseases. ◦ More to follow…