Download Prokaryotes - AP Biology Overview

Prokaryotes
Cell wall
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Polysaccharides - Archaea
Peptidoglycan - Bacteria
o Gram positive – simple cell wall with LOTS of peptidoglycan
o Gram negative – complex cell wall with little peptidoglycan
 More pathenogenic and disease causing – can be resistant to antibiotics
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Capsule – covers outer cell wall – sticky protection from host cells
Fimbriae – short numerous hairs that attach prokaryotes to one another
Pili – longer hair – can be used for conjugation – DNA transfer from one bacteria to another
Movement
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Flagella – propulsion
Taxis – response toward a stimulus
Reproduction
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Binary Fission – rapid
o Genetic Recombination – Conjugation, transduction, transformation
Adaptation
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Can withstand harsh conditions
Can produce endospores – resistant “dormant cells” (capsules) that can withstand extreme conditions for long
periods of time
Nutrition
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Autotrophs
o Photoautotrophs – photosynthesis
o Chemoautotrophs – use inorganic chemicals in place of sunlight to manufacture organic compounds
Heterotrophs
o Photoheterotrophs – use light for energy, but must get carbon from an organic compound
o Chemoheterotrophs – must consume to get energy and carbon
Metabolism
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Nitrogen
o Nitrogen fixation – take atmospheric nitrogen (N2) to ammonia (NH3) – symbiotic relationship with
some plants
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Oxygen
o Obligate aerobes – use O2 for respiration and cannot grow without it
o Facultative anaerobes – use O2 if present, but can also grow using fermentation
o Obligate anaerobes – are poisoned by O2 – can only do fermentation or anaerobic respiration