Prokaryotes and eukaryotes 

Eukaryotic cell structure

}}Nucleus}}

  • Nucleus = surrounded by double membrane called the nuclear envelope
  • Nucleus = Contains nuclear pores to allow molecules to enter and leave
  • Nucleus = Contains chromatin and a nucleolus (where ribosomes are produced)

}}Rough endoplasmic reticulum}}

  • RER = series of flattened sacs enclosed by a membrane with ribosomes on the surface
  • RER = It folds and processes proteins made by ribosomes

}}Smooth endoplasmic reticulum}}

  • SER = series of membrane bound sacs
  • SER It synthesise and processes lipids and steroids

}}Golgi apparatus}}

  • Golgi = stacked fluid filled, flattened and curved sacks called cisternae
  • Golgi = Has vesicles surrounding the edges
  • Golgi = Sorts, processes and packages proteins and lipids
  • Golgi = Produces lysosomes
  • Golgi = Also modifies proteins into lipo/glycoproteins

}}Centrioles}}

  • Centrioles = hollow cylinders containing a ring of micro tubules arranged in a 9+2 arrangement
  • Centrioles = Involved in cell division (pull chromosomes apart from the equator)

}}80s ribosomes}}

  • 80s ribosomes = composed of a large 60s subunit and a small 40s subunit
  • 80s ribosomes = Where protein synthesis occurs

}}Lysosomes}}

  • Lysosomes = vesicles containing digestive enzymes
  • Lysosomes = Bound by a single membrane

}}Mitochondria}}

  • Mitochondria = bound by a double membrane called the envelope

  • Mitochondria = Inner membrane is folded into cristae

  • Mitochondria = Has a matrix on the inside containing enzymes needed for aerobic respiration

Prokaryotic cell structure

<<Cell wall<<

  • Cell wall = ridged outer covering made of peptidoglycan
  • Cell wall = Provides cell with support and strength

<<Slime capsule<<

  • Capsule = protective slime layer which helps cells retain moisture
  • Capsule = Helps adhere to surfaces

<<Plasmid<<

  • Plasmid = circular piece of extra DNA

<<Flagellum<<

  • Flagellum = tail like structure that rotates to move the cell

<<Pili<<

  • Pili - hair like structures which attach to other bacterial cells
  • Allow plasmids to move from cell to cell

<<70s ribosomes<<

  • 70s ribosomes = composed of a large 50s subunit and small 30s subunit
  • 70s ribosomes = Site of protein synthesis
  • 70s ribosomes = Smaller than the eukaryotic ribosomes

<<Mesosomes (artefact)<<

  • Mesosomes = in folding of the inner membrane which contain enzymes needed for respiration

Bacterial cell wall

  • bacteria can be classified according to their shape and their reaction to gram stain

    Gram positive

    • cell wall made of a thick layer of peptidoglycan, and an inner plasma membrane (phospholipid bilayer)
    • Will stain violet after having gram stain put on it as the crystal violet stain binds to the peptidoglycan cell wall

    Gram negative

    • cell wall made of a thin layer of peptidoglycan with an outer lipopolysaccharide membrane and an inner phospholipid bilayer
    • Wont stain with gram stain as the peptidoglycan isn’t available to bind to
    • Will stain pink after washing with ethanol and using red Safranin

Bacteria and medication

  • different antibiotics are needed for gram positive and gram negative bacteria
  • Gram positive bacteria release exotoxins whilst alive and make you feel ill quicker
  • Gram negative bacteria release endotoxins when dead and make you feel ill after a while