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. Rough and smooth ER

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

5. 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 other molecules to the protein, which can help the protein to fold – determining its purpose in the cell – and gain stability (as a molecule).

6. 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.

7. Rough and smooth ER

8. Golgi Apparatus (GA)
From ER, proteins typically move to Golgi apparatus by transport vesicle.
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.

9. Golgi Apparatus (GA) and Transport Vesicles

10. Transport Vesicles
Vesicles are made when tiny piece of protein-containing ER is pinched off. This allows the protein to be safely transported to the GA.
They separate proteins from the cytoplasm and transport them from place-to-place within the cell – they are short-lived.

11. Golgi Apparatus (GA) and Transport Vesicles