Structure and Function of Bacteria

Kingdom Archaebacteria Extreme environments Methanogens – Make methane gas, anerobic Halophiles – salt loving, use salt to make ATP Thermoacidophiles – extreme acid & temperature environments.

Kingdom Eubacteria Cell walls composed of peptidoglycan.

Shapes of Bacteria Coccus – Round Bacillus – rod shaped Spirillum – spiral shaped

cocci rod helical spirillum

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 peptidoglycan Pink: Gram negative have an outer membrane and some peptidoglycan

Motility Flagellum Pili – help bacteria stick together. Secrete slime to help anchor bacteria to a surface and glide.

Binary Fission Makes 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

Summary 3 characteristics used to classify bacteria Shape Round Rod Spiral Cell Wall Structure Mostly peptidoglycan Peptidoglycan surrounded by a membrane Motility Reproduction – Binary Fission