Notes 9-2 Bacteria

2 Kingdoms Most scientists agree that there are 2 Kingdoms of bacteria 1) Archaebacteria (very ancient) 2) Eubacteria (“true” bacteria)

The Bacterial Cell Prokaryotic (No nucleus, so genetic material and ribosomes are floating in cytoplasm) Circular DNA Cell walls May have flagella

Discovery Discovered in late 1600s by Anton van Leeuwenhoek using a microscope

Shapes of bacteria 3 Shapes: 1) Spirilla are spiral, Bacilli are rod- like, and Cocci are circular You can often tell the shape of the bacteria by its scientific name.

Bacillus Anthracis Can you tell the shape of this bacteria by its name? It’s shape is bacilli or rodlike! This bacteria causes anthrax!

Streptococcus pyogenes Can you tell the shape of this bacteria by its name? It’s shape is cocci or sperical! This is one of the bacterias that cause strep throat!

Living conditions Many can survive harsh conditions by growing protective capsule called endospores inside Some are autotrophs, they make their own food using sunlight or chemicals Some are heterotrophs that consume food such as other living organisms or dead/ decaying matter Some need oxygen and some do not, some will die in presence of oxygen!

Endospore Protects DNA until environmental conditions are right for survival

Reproduction Asexually by binary fission (cell copies its DNA, then splits into 2 identical cells) Sexually by conjugation (bridge built between 2 bacteria and DNA is inserted, then divides asexually by binary fission, genetically different from parent cell)

Role in Nature Release O2 gas into air we breathe Both food production and spoilage Environmental recycling (they’re decomposers like fungi) Environmental cleaning Some cause diseases, some used to make medicines Found naturally in body and help many processes