Prokaryota

Core Concepts

Prokaryotes are classified into two domains/kingdoms: Bacteria and Archaea Presence of peptidogycan in bacteria Some archaea have pseudopeptidoglycan

Diverse cell wall, some made up of proteins called S layer

Bacteria are identified by their shapes, the chemical natures of their cell walls, the ways they move and the ways they obtain and use energy

Bacteria reproduce asexually by binary fission. Through the process of conjugation, genes can move from one cell to another, thus increasing genetic diversity within bacterial populations

Prokaryotes play a crucial role in the biosphere, such as taking part in nutrient cycles and in symbiotic relationships. Also, they have both harmful and beneficial impacts on humans

Keywords

Prokaryte bacteria archaeaPeptidoglycan coccus bacillusSpirillum Gram-negative Gram-positiveFlagellum autotroph heterotrophPhototroph chemotroph aerobeFacultative anaerobe obligate/strict

anaerobeBinary fission conjugation endospore

Some things to remember

Basis for split- presence/absence of peptidoglycan, genetic differences

Eubacteria and archaebacteria are misleading

Archaeans are more closely related to eukaryotes than to bacteria

Use of domain scheme suggests that the split between bacteria and archaea are more ancient than the split between prokaryotes and eukaryotes

S layer and peptidoglycan

Archaea with an S layer

Representatives

Bacteria-cyanobacteria

Archaea- methanogens, thermophiles, halophiles

Identification of bacteria

Cell shape- coccus, bacillus, spirillum, strep/staph

Cell wall composition- gram-negative/positiveMotility- flagellaNutrition and metabolism-

Auto/hetero Photo/chemo Aerobic/anaerobic/facultative

Bilog, streyt, paikot-ikot, sama samang bilog

Positive o negative

Growth and reproduction

Binary fission- no new combination of genesConjugation- increases genetic diversityEndospore-formation- enebles survival in

harsh conditionsControl of bacterial growth

Sterilization vs disinfection refrigeration

Ecology of bacteria

Some bacteria take part in the recycling of elements

Some bacteria form symbiotic relationships with other organisms

Some bacteria are pathogensSome bacteria play important roles in

research and technology