Bacteria characteristics

• Cyanobacteria


  Earlier called the blue-green algae
• Cyanobacteria


  • Could carry out photosynthesis
  • Oxygen released during the process changed the earth's atmosphere and gradually the level of oxygen increased in the earth's atmosphere
• Parts of a cyanobacterial cell

  • Cell wall
  • Cell membrane
  • Position of DNA
  • Slime layer
  • Ring of DNA
  • Food granules
  • Ribosome
  • Mesosome
  • Pili
• Bacteria


  • Smaller cells
  • May have flagella
  • Some bacteria carry out photosynthesis in a different way and do not release oxygen (anoxygenic)
• Cyanobacteria


  • Larger cells
  • Do not have flagella
  • Carry out photosynthesis in the usual manner as in green plants and release oxygen (oxygenic)
  • Sexual recombination has been observed in some cyanobacteria
• Azotobacter fix atmospheric nitrogen in the soil
• Lactobacillus set milk into curd
• Mycobacterium tuberculosis cause tuberculosis
• Clostridium tetani cause tetanus
• Approximately 8 bacteria may be obtained from one bacterium in an hour
• Bacteria


  • Smaller cells
  • May have flagella
  • Sexual recombination by conjugation in some bacteria
• Cyanobacteria


  • Larger cells
  • Do not have flagella
  • Sexual recombination has been observed in some cyanobacteria
• The single celled bacterium has a circular single chromosome made of the chemical compound peptidoglycan covering the cell membrane
• The special region in the bacterial cell where genetic material lies is called the nucleoid
• Cell wall


  Made up of the chemical peptidoglycan, lipids, polysaccharides, and some protein
• Flagella


  Longer and thicker compared to Pili, which are shorter and thinner thread like structures
• Aerobic bacteria


  Need oxygen for their energy
• Anaerobic bacteria


  Don't need oxygen at all, can live without oxygen
• During sexual recombination in a bacterium, a segment of DNA strand is transferred from one bacterium to another