1. Cell Organelles Section 3.2, Part 2

2. Endoplasmic Reticulum (ER) An interconnected network of thin folded membranes (forms maze of enclosed spaces). – Interior of the “maze” is the lumen. Fills a large part of a eukaryotic cell’s cytoplasm. The folds allow for lots of surface area to carry out its processes. Processes – production of proteins and lipids inside, in the lumen, and on the surface of it.

3. Ribosomes Either found on the surface of the ER or independently suspended in the cytoplasm. Processes: they are the site of protein synthesis (and themselves are made of proteins). – They link amino acids, found in cytoplasm, together to form proteins. They are built in the nucleolus in the nucleus.

4. Ribosomes and rough ER work together Ribosomes and rough endoplasmic reticulum (rough ER), work together. – Ribosomes attached to the outside surface of the rough ER make proteins. – The proteins enter the rough ER and are modified in the lumen. The lumen can add sugar chains to the protein, which can help the protein to fold – determining its purpose in the cell – and gain stability (as a molecule).

5. Smooth ER Some ER does not have ribosomes, it is called smooth ER. Processes: smooth ER produces lipids and other functions like breaking down drugs and alcohol (it is a detoxifier when you poison yourself). Alcoholics and drug addicts have lots of smooth ER – much more than “normal” humans.

6. Rough and smooth ER

7. Golgi Apparatus (GA) From ER, proteins typically move to Golgi apparatus. Process: they process, sort, “package,” and deliver proteins to where they need to go. GA is made of closely layered stacks of membrane-enclosed spaces. The packaged proteins can be stored in the GA; sent to other organelles in the cell; or shipped outside of the cell.

8. Transport Vesicles Small membrane-bound sacs that separate chemical reactants until it is time for them to be used. Separate the chemicals from the cytoplasm and transport the chemicals from place-to- place within the cell – the are short-lived. Vesicles are made when tiny piece of protein- containing ER is pinched off. This allows the protein to be safely transported to the GA.

9. Golgi Apparatus (GA) and Transport Vesicles