Workers in this part of the plant are responsible for making minor adjustments to the finished products. They inspect the products for flaws, clean them of any extra material added during their manufacture, wrap them, and target them for packing. The Golgi apparatus performs all these tasks in the cell.

Golgi Apparatus Structure

The Golgi apparatus receives ER proteins and modifies them prior to shipping.

Golgi Apparatus Function

Animation of exocytosis

Eventually, some of the smooth ER membrane is pinched off as a SPHERICAL VESICLE. The proteins are either contained inside these structures or are carried on their surfaces. These vesicles are absorbed by the Golgi apparatus, and proteins are processed as they pass from one sac to the next. As the proteins move they are processed. When the protein is ready for export, it is pinched off of the Golgi and released into the cytoplasm.

What becomes of the final product of protein synthesis once it enters the cytoplasm? Some of these proteins eventually become membrane proteins and help with the functions of transport or self-recognition. These proteins are carried on the outside of the spherical vesicles and transported to the plasma membrane. Some of these proteins are retained within the cytoplasm for use by the cell.

Proteins are received by the cis face of the Golgi and exit through the trans face after modification.

Other proteins are stored inside the vesicles until they are needed for export. Hormones and enzymes are stored in this fashion until released though the plasma membrane in a process known as exocytosis. EXOCYTOSIS, a type of active transport, occurs when a vesicle inside a cell fuses with the cell's membrane and releases its contents to the outside environment.

All of this production leaves behind quite a mess! Who cleans up the trash?

BACK | LINKS | NEXT