Module 5

• Bacteria are one of the most harmful microorganisms that cause diseases specifically infections to many living things
• Bacteria


  Single-celled organisms that lack nucleus or any membrane-bound organelle
• Prokaryotic Cell


  Classification of bacteria
• Cellular components of bacteria

  • Cell wall
  • Capsule
  • Cytoplasm
  • Plasma membrane
  • Ribosomes
  • Flagella
  • Pili
  • Plasmid
  • Nucleoid
• Cell wall


  • Provides support, mechanical strength and rigidity
  • Protects cell from bursting in hypotonic medium
• Capsule


  • Keeps the bacterium from drying out
  • Protects from phagocytosis
• Cytoplasm


  • Store house of all chemicals and components for sustaining life
• Plasma membrane


  • Semi-permeable membrane
  • Allows selected materials to move in and out
• Ribosomes


  • For protein synthesis
  • Helps in transferring genetic material
• The main difference between bacterial ribosomes and eukaryotic ribosomes is that some antibiotics will inhibit the function of bacterial ribosomes, but not in the case of eukaryotes
• Flagella


  • Means of locomotion
  • Helps the bacterial cell to move in clockwise and counter-clockwise
• Pili


  • Assist in attaching to surfaces
  • Involved in gene transfer mechanism called sex pili
• Gene transfer through pilus

  1. From donor to recipient cell

  2. Called conjugation
• Plasmid


  • Small circular DNA
  • Exchanges DNA between bacterial cells
• Nucleoid


  • Irregularly-shaped section where DNA is housed
  • Lacks membrane found in eukaryotic nucleus
• Nucleoid


  • Contains RNA, proteins and enzymes used for cellular processes
• Capsule - Protective covering of bacteria made of polyccharide
• Cytoplasm - for cellular growth, metabolism and replication of genetic material of bacterial cell.
• Flagella- only be found mostly in prokaryotes like bacteria.
• Pili-small hair like projections
• Plasma membrane helps in transportation of substances including removal of wastes from the body and providing mechanical barrier to the cell