What are Bacteria? Bacteria are PROKARYOTES (what does that mean?) –The smallest known living cells They are found everywhere!! Bacteria on head of a pin Bacteria in dental plaque Did you know? There are over 80 species of bacteria in your mouth!

Some cause disease We call these pathogens Anthrax, as seen by Koch But most are beneficial Bacteria ferment cheese

Characteristics of Bacteria Most have a cell wall Many have a capsule ( jelly or slimy coating outside the cell wall, for protection) They have a single, circular chromosome. Schraer, 632

Some have flagella - made of rope-like proteins, not microtubules. Some slide on a slimy secretion.. Salmonella Streptomyces spores Many can MOVE

Three basic shapes Spherical – coccus Rod – bacillus Coiled - spirillum Schraer, 633

Simple Colonies Staphylo = clusters Strepto = chains Staphylococcus wisc.edu Diplo = double Diplococcus cat.cc.md.us Streptobacillus

Normal bacterial reproduction 1) chromosome replicates 2) copies separate as cell wall lengthens 3) cell membrane pinches in 4) septum/new wall grows 5) cells divide Steps in binary fission maricopa.edu Bacillus dividing by fission SixKingdoms.html Binary fission (for a quick clone)

See Fission in Action Did you know? In ideal conditions, some species can divide every 10 MINUTES. What stops them? They run out of food or space, or wastes build up and poison them.

How antibiotics work Kill Bacteria Basically they do something that prevents that bacteria from living and reproducing Antibiotics are designed to work specifically on bacterial cells, not eukaryotic cells (They dont kill healthy cells)