Question

What is the process of synthesizing cell membrane using proteins and lipids?

Answer 1

Membrane biosynthesis:

1. It is a process to synthesize the cell membrane using protein and lipids.
2. Membrane proteins are synthesized in the rough endoplasmic reticulum while lipids are manufactured by the smooth endoplasmic reticulum and Golgi apparatus.
3. Membranes and their constituent proteins are assembled in ER.
4. This organelle contains enzymes involved in lipid synthesis, and since lipids are made by ER, they are inserted into the organelle's membrane.
5. Similarly, transmembrane proteins have a hydrophobic surface sufficient to be incorporated into the endoplasmic reticulum membrane, even during synthesis.
6. This is where future membrane proteins reach the endoplasmic reticulum membrane using the newly translated protein signaling sequences.
7. The signaling sequence stops translation and directs the ribosome, which carries the unfinished protein, to dock with the ER protein before it finishes its job.
8. Translation begins again after the signal sequence docks to the endoplasmic reticulum and occurs within the endoplasmic reticulum membrane.
9. Therefore, when the protein reaches its final form, it is already incorporated into the membrane.
10. Proteins secreted by cells are sent to the ER during translation, where they eventually reach the lumen, where they are packaged for vesicle release from the cell.
11. Examples of vesicular proteins are insulin and erythropoietin (EPO).