AS Biology - Cell Structure - Organelles

Organelles & Protein Production

• Proteins are made at the ribosomes
• Ribosomes on rough endoplasmic reticulum make proteins that are excreted or attached to the cell membrane.The free ribosomes in the cytoplasm make proteins that stay in the cytoplasm. 
• New proteins at the rough endoplasmic reticulum are folded and processed (e.g. sugar chains are added).
• They're transported from the endoplasmic reticulum to the Golgi apparatus in vesicles
• At the Golgi apparatus the proteins may undergo further processing (e.g sugar chains are trimmed or added).
• Proteins enter more vesicles to be transported around the cell. E.g. extracellular enzymes (like digestive enzymes) move to the cell surface and are secreted.

Functions of the cytoskeleton

• Organelles in cells are surrounded by the cytoplasm. The cytoplasm is more than just a solution of chemicals - it's got a network of protein threads running through it - these are called the cytoskeleton.
• In eukaryotic cells protein threads are arranged as microfilaments (small solid strands) and microtubules (tiny protein cylinders).
• They have 4 main functions:
  1) Microtubules and microfilaments help support the cell's organelles keeping them in position
  2) Help strengthen the cell and maintain its shape
  3) Responsible for transport of…