Microorganisms 🦠

• Prokaryotes versus Eukaryotes refers to the internal structure of cells and how to tell the difference
• Prokaryote


  Cells with a primitive nucleus or primitive organelles
• Eukaryote


  Cells with a more modern nucleus or a set of organelles surrounded with a membrane
• Prokaryotic and eukaryotic cells both have DNA, ribosomes for protein synthesis, and a cell membrane
• Eukaryotic cells


  • Have a membrane-enclosed nucleus
  • Have membrane-bound organelles like mitochondria, Golgi body, endoplasmic reticulum
• Prokaryotic cells


  • Have DNA freely floating in a nucleoid
  • Lack many membrane-bound organelles
• Viruses


  Acellular organisms that cannot carry out the seven basic life functions and can only exist within a host
• Viruses


  • Can be spherical or rod-shaped
  • Have a protective capsid protein coat
  • Some have an additional envelope layer
• Bacteriophage


  A type of virus that infects bacterial cells, attaching with tail fibers and injecting its DNA
• Viruses can cause many fatal diseases like polio, HIV, foot and mouth disease
• Bacteria


  • Unicellular organisms that can exist as single cells or in colonies
  • Classified by their shape: cocci, bacilli, vibrios, etc.
• Bacterial cell structures


  • Capsule for protection
  • Cell wall for rigidity and protection
  • Plasma membrane
  • Freely floating DNA (nucleoid)
  • Ribosomes
  • Lack membrane-bound organelles
  • Plasmids for faster replication and adaptation
  • Flagella/flagellum for movement
  • Pili for attachment to host
• Protists


  A diverse group that can be unicellular or multicellular, sharing characteristics with both prokaryotes and eukaryotes
• Protists have a nucleus, membrane-bound organelles, and can be unicellular or multicellular
• Unicellular


  One cell, living on their own often in a body of water
• Multicellular


  Many cells making up one organism, e.g. seaweed
• Protists


  • Have a nucleus and membrane-bound organelles
  • Many are photosynthetic, making up the majority of ocean plankton
• Contractile vacuole


  Unique to protists, regulates water absorption to prevent drowning
• Flagellum


  Tail-like structure for movement, found in both protists and bacteria
• Food vacuole


  Where protists store and digest food
• Pseudopodia


  False feet used by protists to surround and digest food
• Fungi


  • Cannot photosynthesize, instead absorb nutrients from dead or dying matter
  • Can be unicellular or multicellular
• Hyphae


  Long, interconnected fungal cells that lack cell walls between them
• Rhizoids


  Root-like structures used by fungi to absorb nutrients
• Stolon


  Horizontal hyphae growing above the substrate
• Mycelium


  The entire body of a fungus, including hyphae, rhizoids, and stolons
• Sporangiophore


  Structure that produces spores for fungal reproduction
• Sporangium


  The spore-containing structure at the end of a sporangiophore
• Terminology recap


  • Prokaryotes
  • Eukaryotes
  • Viruses
  • Capsid
  • Envelope
  • Pathogenic
  • Bacteria
  • Coccus
  • Bacillus
  • Spirillum
  • Flagella
  • Pili
  • Plasmid
  • Protists
  • Contractile vacuole
  • Food vacuole
  • Pseudopodia
  • Fungi
  • Saprophytic
  • Hyphae
  • Rhizoids
  • Stolon
  • Mycelium
  • Sporangiophore
  • Sporangium