B2.2.1

• Organelles are discrete structures in cells that are adapted to perform one or more vital functions.
• Organelles with no membrane:

  • Ribosomes
  • Centrioles
  • Microtubules
  • Proteasomes
  • Nucleoli
• Organelles with single membrane:

  • vesicles and vacuoles
  • rough endoplasmic reticulum
  • smooth endoplasmic reticulum
  • Golgi apparatus
  • lysosomes
• organelles with a double membrane:

  • Nuclei
  • Mitochondria
  • Chloroplasts
  • Amyloplasts
  • Chromoplasts
• Some structures are not considered organelles:

  • cell walls
  • cytoskeletons
  • cytoplasm