Prokaryote Microorganisms 11.0 Classify animals according to type of skeletal structure, method of fertilization and reproduction, body symmetry, body coverings, and locomotion. Examples: skeletal structure - —vertebrates, invertebrates; fertilization—- external, internal; reproduction -—sexual, asexual; body symmetry—- bilateral, radial, asymmetrical; body coverings—- feathers, scales, fur; locomotion—- cilia, flagella, pseudopodia

Prokaryotes:  What is a prokaryote?  Lack a nucleus  Unicellular  What 2 Kingdoms would include prokaryotes?  What 2 Domains would include prokaryotes?  Recall that under the 5 Kingdom Classification System, ALL prokaryotes were included in one kingdom – Monera.

Eubacteria (Domain Bacteria)  Found almost everywhere  Usually surrounded by a cell wall that protects it and determines its shape.  Cell walls contain peptidoglycan  _________________ surrounds the cytoplasm inside the cell wall. Source:

Archaebacteria (Domain: ??)  Lack peptidoglycan in the cell wall  Have membrane lipids not found in other organisms  Can be found in extreme environments  DNA sequences of key genes are more like those of eukaryotes than eubacteria

Identification of Prokaryotes: 1. Shape: a. Bacilli – rod-shaped b. Cocci – spherical c. Spirilla - spiral and corkscrew-shaped 2. Cell walls – Gram staining a. Violet (primary) stain stains the peptidoglycan b. Alcohol wash will rinse the stain from thin- membraned organisms (Gram -), but not from thick-walled (Gram +). c. Red (counterstain) will make Gram - organisms look pink or light red. 3. Movement – no movement, flagella, snakelike movements, or gliding along secreted slime.

Source: eas/EUBACTERIA/eubacteria.html

Metabolic Diversity  Heterotrophs:  Chemoheterotrophs – use organic (carbon-based) compounds for energy  Photoheterotrophs – use light for energy, but also need organic compounds for carbon  Autotrophs:  Photoautotrophs – use _______ to convert ____ and _____ to ________ and ________.  One type of photoautotroph is cyanobacteria, which contain a bluish pigment and chlorophyll .  Chemoautotrophs:  make organic molecules from CO 2, but without light  Use energy from chemical reactions occurring around them

Growth & Reproduction 1. Binary fission – a bacterium doubles in size, duplicates its DNA, and divides in half. 2. Conjugation – the exchange of DNA across a hollow bridge formed by intertwined pili. 3. Spore formation – under adverse conditions, some organisms can form a thick internal wall around its DNA until conditions are more favorable.  Summary: some sexual, some asexual methods

Why Are Bacteria Important?  Decomposers  Nitrogen fixers for plants  Human uses:  Foods and beverages  Clean up oil spills  Synthesize drugs and chemicals  Help us digest foods