Bacteria What you don’t know CAN hurt you!

(Bacteria Review) What do you already know about bacteria??

Major Episodes in the History of Life Visual Summary 15.1 Millions of years ago ,000 1,700 2,500 3,500 4,500 Major Episode Plants and fungi colonize land All major animal phyla established First multicellular organisms Oldest eukaryotic fossils Accumulation of atmospheric 0 2 Oldest prokaryotic fossils Origin of Earth

Two types of Prokaryotic organisms: Eubacteria (bacteria) and Archaea Visual Summary 15.3 Prokaryotes Domain Bacteria Domain Archaea (e.g., extremophiles)

Prokaryotic and eukaryotic cells differ in several respects Figure 4.4 Prokaryotic cell Nucleoid region Eukaryotic cell Nucleus Organelles

The Two Major Categories of Cells SUMMARY OF KEY CONCEPTS Visual Summary 4.1

Review of Prokaryote Structure Plasma membrane Outer cell wall Big loop of DNA Little loops of DNA (plasmids) Ribosomes Cytoplasm

Generalized structure of bacteria cell

Figure4.5x2

What’s going on?

Detriments to Humans Bad breath, tooth decay Food poisoning Some are pathogenic pathogenic – Some diseases caused by bacteria: Strep throat, “staph” infection Cholera, “The Plague”, anthrax Syphilis, gonorrhea,

How cure bacterial infections? (Antibiotics)

Homework: Should we drop “bacteria bomb?” Are there benefits to bacteria that outweigh their detriments to humans?

Benefits of Bacteria Decomposers!  chemical cycling Cyanobacteria were original producers of oxygen atmosphere  ozone Origins of mitochondria & chloroplasts Aid humans in digestion (E. coli) Allow cows to digest cellulose (grass)  milk, ice cream, hamburgers! Lactic acid fermentation (yogurt, buttermilk, sauerkraut) bioremediation Nitrogen “fixers” (to be explained in Unit IV!)

End