Week 2

• Prokaryote or pro-karuon-ote


  Translates to before nut or kernel
• Prokaryotic cells


  • No nucleus and no organelles
  • Two types/domains: Bacteria and Archaea
  • Very diverse! They have many different structures that help them survive in many different environments
  • Relatively simple structures e.g. bacterial cells are small (200 nm to 2 micrometers) with complex chemistry
• Bacterial cell


  • No membrane-bound nucleus and no energy-producing organelles
  • DNA is present as a single circular chromosome in the nucleoid
  • Can carry additional DNA in the form of plasmids
  • Commonly found as spheres, rods, spirals, or filaments

  
• Eukaryote or eu-karyo-ote


  Translates to formed nut or kernel
• Eukaryotic cells


  • Nucleus and other specialized structures inside of the cell
  • Membrane bound organelles
  • Different structures for different environments/functions
  • Complex chemistry occurs in inside and outside of organelles
  • The dynamic cytoskeletal and membrane systems give eukaryotes the structure required for larger cells with complex shapes and the ability to ingest other cells

  
• All of the cells pictured are specialized forms of human eukaryotic cells

  
• Their structure is directly related to their function
• Eukaryotic cytoskeleton


  • Made up of protein fibers e.g. microfilaments and provides internal support
  • Intermediate filaments are specific to animal cells
  • Bacteria have a cytoskeleton too!

  
• Viruses are similar to other living organisms in that they have the ability to store and transmit genetic information in DNA and RNA
• Viruses are dissimilar to other living organisms in that they don't have the ability to harness energy from the environment, carry out metabolic reactions on their own, and use a cell as a host to replicate and read/use their genetic material