The Endoplasmic Reticulum is an organelle that forms an interconnected network of membrane vesicles.

Structure

There are three different types of ERs:

• Rough Endoplasmic Reticulum (RER)
  • Has ribosomes attached to the outside
  • These ribosomes synthesise protein
  • Connects to the Nuclear Envelope
• Smooth Endoplasmic Reticulum (SER)
  • Produces lipids
  • Cholesterol metabolism
  • Lipids are sent to golgi in vesicles
• Sarcoplasmic Reticulum (SR)
  • An SER found in smooth and striated muscle

Function

• Many general functions - can adapt to what the organism needs
• e.g.
  • Production of hormones
  • Cholesterol metabolism
  • Membrane synthesis
  • Lipid production