39. Proteins are manufactured from the "blueprints" found on DNA. After they are translated, they are moved through a system of internal membranes before being distributed throughout the rest of the cell. At some point in this process, they are modified to their functional form.
In your own words, discuss the role of each of the following structures in the whole process: cell membrane, vesicles (at two points in the process, ribosomes, Golgi apparatus, and endoplasmic reticulum. Be sure to identify the correct order in which the proteins move through each of these structures.
My answer:
Proteins are produced by ribosomes on the rough part of the endoplasmic reticulum. These proteins are then packed into vesicles. Next, the proteins are moved from the rough ER to the Golgi apparatus by means of vesicles. Processing of the proteins takes place in the Golgi apparatus, after which they are packaged into new vesicles. Some vesicles then release their proteins outside the cell. Remaining vesicles stay inside the cell and become lysosomes.
Is this OK?
Thanks
-MC
Great job! Your answer is mostly correct, but there are a few minor adjustments needed to accurately explain the role of each structure in the process.
Here's a revised version:
Proteins are manufactured from the instructions encoded in the DNA. This process begins with the synthesis of proteins on ribosomes, which are either free in the cytoplasm or attached to the rough endoplasmic reticulum (ER). The ribosomes on the rough ER help in the production of proteins that are destined to be modified and transported.
As the newly synthesized proteins are formed on the ribosomes, they are moved into the lumen (internal space) of the rough ER. Here, the proteins undergo initial modifications and folding to attain their functional shape.
From the rough ER, the proteins are then packaged into transport vesicles. These vesicles bud off from the rough ER and carry the proteins to the Golgi apparatus. The role of the vesicles is to transport the proteins between different compartments within the cell.
Once the transport vesicles arrive at the Golgi apparatus, the proteins undergo further processing. This includes modifications such as enzymatic additions or removals, as well as sorting and packaging into distinct vesicles.
The Golgi apparatus acts as a processing and sorting station. It modifies the proteins and directs them to their final destinations according to their specific functions. The Golgi apparatus also plays a role in the production of certain types of carbohydrates that can be attached to proteins.
After the proteins are processed within the Golgi apparatus, they are packaged into new vesicles. Some of these vesicles will transport the proteins to the cell membrane, where they can be released outside the cell via exocytosis, playing a role in cell signaling or communication.
On the other hand, some of the vesicles derived from the Golgi apparatus stay inside the cell and become lysosomes. Lysosomes contain enzymes that degrade materials no longer needed by the cell, including unwanted proteins.
So, the correct order of movement for the proteins through each structure is as follows: ribosomes (rough ER) → rough ER → transport vesicles → Golgi apparatus → new vesicles (for secretion or lysosomes).