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