BACTERIA

BACTERIA (Prokaryotes) Characteristics of Bacteria: plasma membrane – controls what enters and leaves the cell cell wall – gives shape and support capsule - thick sticky coat that helps it stick to its host flagella – used for movement ribosomes – makes proteins circular piece of DNA; no membrane bound organelles pili – short projections used to trade pieces of its DNA with other bacteria through conjugation

conjugation – a process in which 2 organisms exchange genetic material, in prokaryotes, pili (pilus) from one bacterium adheres to a second bacterium to spread genes within a population

Bacterial Structure

Bacteria Classification: Archaeabacteria – have cell walls with no peptidoglycan; they are extreme bacteria; they live in extreme habitats; Methanogens – produce methane gas Thermophiles – live in hot sulfur springs Halophiles – live in bodies of concentrated salt water 2. Eubacteria – have cell walls made of peptidoglycan: consists of helpful and harmful bacteria

Bacterial Shapes: bacillus – rod shaped cell coccus – round shaped cell spirillum – spiral shape

Arrangement of Bacteria Cells Single Pair Chain Cluster

endospores – a thick wall that forms around chromosomes and a small bit of cytoplasm; when bacteria are exposed to harsh conditions, such as, lack of nutrients, drought, or high temperatures (environmental stress), the endospore can survive and may germinate years later releasing new active bacteria