Formation of Extracellular Enzymes
- In cells, many organelles are involved in the production and secretion of proteins
- Organelles are specialised parts of a cell that carry out a particular function
- Some organelles are membrane-bound, meaning that they are surrounded by membrane
- The organelles involved in protein synthesis include
- Nucleus
- Transcription of the DNA code occurs here
- Ribosomes
- Free ribosomes and those on the RER produce proteins in the process of translation
- Rough endoplasmic reticulum (RER)
- Golgi apparatus
- Cell surface membrane
- Proteins formed within the cell are secreted here
- Nucleus
Rough endoplasmic reticulum
- Ribosomes on the RER produce proteins that can be secreted out of the cell or become attached to the cell surface membrane
- Proteins that have been passed into the lumen of the rough endoplasmic reticulum are folded and processed here
- The term lumen refers to the inside space of the RER
- Note that free ribosomes found within the cytoplasm make proteins that stay within the cytoplasm rather than being moved to another organelle or being exported from the cell
Golgi apparatus
- Processed proteins from the RER are transported to the Golgi apparatus in vesicles which fuse with the Golgi apparatus, releasing the proteins into the Golgi
- The Golgi apparatus modifies the proteins, preparing them for secretion
- Proteins that go through the Golgi apparatus are usually
- Exported, e.g. extracellular enzymes
- The term extracellular refers to 'outside the cell'
- Put into lysosomes, e.g. hydrolytic enzymes
- Delivered to other membrane-bound organelles
- Exported, e.g. extracellular enzymes
- The modified proteins then leave the Golgi apparatus in vesicles
The RER and Golgi apparatus are involved with producing, packaging and transporting proteins in a cell. This process can be used to produce and export extracellular enzymes.