structure and function of bacteria. kingdom archaebacteria extreme environments methanogens – make...
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Structure and Functionof Bacteria
Kingdom Archaebacteria
Extreme environmentsMethanogens – Make methane gas, anerobicHalophiles – salt loving, use salt to make ATPThermoacidophiles – extreme acid &
temperature environments.
Kingdom Eubacteria
Cell walls composed of peptidoglycan.
Shapes of Bacteria
Coccus – Round
Bacillus – rod shaped
Spirillum – spiral shaped
cocci
rod
helicalspirillum
Cell Wall Structure
Two types of cell walls
1. Composed mainly of peptidoglycan
2. Less peptidoglycan with an additional outer membrane.
How do we distinguish between types of cell walls?
Gram Staining –
Purple: Gram Positive. Have peptidoglycanPink: Gram negative have an outer membrane
and some peptidoglycan
MotilityFlagellum
Pili – help bacteria stick together.
Secrete slime to help anchor bacteria to a surface and glide.
Binary FissionMakes an exact copy of the cell.
Many bacteria can copy themselves every 20 minutes!
Prokaryotes are asexual, so they lack the genetic recombination obtained through meiosis.However, there are three other mechanisms of genetic recombination in Prokaryotes:
1) Transformation - genes taken up from outside environment (dead
bacteria)
2) Conjugation- genes transferred directly from one prokaryote to another
3) Transduction- genes are transferred between prokaryotes by viruses
Transformation
Conjugation
Antibiotic Resistance
The conjugative transfer of antibiotic resistant plasmids between bacteria is a major problem facing the medical profession today
Transduction
Summary3 characteristics used to classify bacteria
ShapeRoundRodSpiral
Cell Wall StructureMostly peptidoglycanPeptidoglycan surrounded by a membrane
Motility
Reproduction – Binary Fission