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