Bacteria

Bacteria Microscopic organisms that are prokaryotes Microscopic organisms that are prokaryotes Make up two kingdoms of the classification system: Make up two kingdoms of the classification system: –Eubacteria –Archaebacteria First organism on earth First organism on earth Highly evolved and very diverse Highly evolved and very diverse

Structure of a Bacteria Chromosomes Chromosomes Capsule Capsule Ribosomes Ribosomes Cell Wall Cell Wall Plasma Membrane Plasma Membrane Flagella - movement Flagella - movement Pili - attachment Pili - attachment

Eubacteria The most common type of bacteria The most common type of bacteria Found almost everywhere except extreme environments Found almost everywhere except extreme environments Strong cell walls made of peptidoglycan Strong cell walls made of peptidoglycan Some have two cell walls Some have two cell walls

Archaebacteria Found in extreme environments Found in extreme environments Thermoacidophiles: found in hot, acidic environments Thermoacidophiles: found in hot, acidic environments Halophiles: found in very salty environments Halophiles: found in very salty environments Methanogens: cannot live in the presence of oxygen Methanogens: cannot live in the presence of oxygen

Bacteria Shapes There are three different shapes of bacteria: There are three different shapes of bacteria: –Cocci (round) –Bacilli (rod-shaped) –Spirilli (spiral-shaped)

Cocci

Bacilli

Spirilli

Reproduction Most reproduce by binary fission Most reproduce by binary fission –The cell divides into two daughter cells –The single chromosome is also duplicated

Reproduction (Continued) Certain bacteria undergo conjugation Certain bacteria undergo conjugation –Genetic information is transferred from one cell to another –New gene combinations are formed

Survival Certain bacteria may undergo Spore Formation to help survive in harsh environmental conditions Certain bacteria may undergo Spore Formation to help survive in harsh environmental conditions –An endospore contains DNA and some cytoplasm –Remains dormant for months or years –Anthrax, botulism, tetanus

Special Types of Bacteria Photoautotrophs Photoautotrophs Chemoautotrophs Chemoautotrophs Aerobes Aerobes Anaerobes Anaerobes Facultative Anaerobes Facultative Anaerobes

Harmful vs. Helpful Bacteria Some bacteria are beneficial Some bacteria are beneficial Others are harmful Others are harmful Micro-viewer lab Micro-viewer lab