Bacteria Our invisible friends

Bacteria are prokaryotes  Pro – before  Karyon – nucleus  The simplest forms of life are prokaryotes without a nucleus.  Earth’s first cells were prokaryotes.

Lots of Them!  Prokaryotes are Earth’s most abundant life forms.  They can survive in many environments.  They can get energy from many different sources.

Prokaryote Review  Mostly single-celled  No nucleus or organelles  Circular chromosomes  Cell walls  Reproduce mostly asexually  Anaerobic or aerobic  Heterotrophic or autotrophic

Archaebacteria  Can survive without oxygen

Eubacteria  Parasitic heterotrophs (Streptococcus)  Saprophages Sapro = death Phage = eat  Include the most ancient prokaryotes

Bacteria are Named by Shape  Cocci (ball-shaped) Streptococcus mutans  Bacillus (rod-shaped) Clostridium botulinum  Spirilli (spiral-shaped) Treponema palladium

Germ Theory of Disease  Joseph Lister – Aseptic Techniques  Robert Koch – Germ Theory A specific microorganism causes a specific disease