2.1.4 Protein Transport

• Endoplasmic Reticulum


  3D network of membrane-bound cavities in the cytoplasm that links to the nuclear membrane and makes up a large part of the cellular transport system as well as playing an important role in the synthesis of many different chemicals
• 80S ribosomes


  Main type of ribososme found in eukaryotic cells, consisting of ribosomal RNA and protein, made up of a 60S and 40S subunit. They are the site of protein synthesis
• 70S ribosomes


  Found in the mitochondria and chloroplasts of eukaryotic cells and in prokaryotic organisms
• Rough Endoplasmic Reticulum (RER)


  Endoplasmic reticulum that is covered in 80S ribosomes and which is involved in the production and transport of proteins
• Exocytosis


  Energy-requiring process by which a vesicle fuses with the cell surface membrane so the contents are released to the outside of the cell
• Smooth Endoplasmic Reticulum


  Smooth tubular structure similar to RER, but without the ribosomes, which is involved in the synthesis and transport of steroids and lipids in the cell
• Golgi Apparatus


  Stacks of membranes that modify proteins made elsewhere in the cell and package them into vesicles for transport, and also produce materials for plant cell walls and insect cuticles
• Lysosome


  Organelle full of digestive enzymes used to break down worn out cells or organelles, or digest food in simple organisms
• Apoptosis


  Programmed cell death - the breakdown of worn out, damaged or disease cells by the lysosomes