Protein Synthesis

Remember these things from the previous post?

The Golgi Apparatus

The Rough Endoplasmic Reticulum

A Ribosome

Yep! They are the Golgi apparatus, the rough endoplasmic reticulum and a ribosome - and together they keep you alive by making proteins! Here's how:
Step 1:
Make a protein...

This is ribosome's job and it all depends on where the ribosome is. If it's in the cytoplasm then the protein doesn't need much work and remains in the cytoplasm for whatever its needed for. However, if the ribosome is attached to the endoplasmic reticulum then it goes through a more complex process. Initially, you could imagine this protein as a flat piece of paper that's unfinished and still needs work. Like this:

This travels into the rough ER for the next step...

Step 2:
Hand it to the rough endoplasmic reticulum...

The rough endoplasmic reticulum is a master of origami and quite literally folds the protein and processes it. Processing can involve adding sugar chains (what they are and how, I don't know yet) so you can imagine the protein paper becoming one of those origami birds with a few sequins stuck on. Like this:

Then the rough endoplasmic reticulum calls upon the cell's favourite post person...

Step 3:
Hand it to a vesicle...

Vesicles... Oops, I didn't add a picture at the beginning. Oh, well, they look like this:

Tiny things! The protein actually travels inside them, like this:

The vesicle will deliver the still unfinished protein to the Golgi apparatus, which is the next step...

Step 4:
Hand it to the Golgi apparatus...

The Golgi apparatus processes the protein further - this time, by not only adding a few more sugar chains (sequins) but trimming the protein too. You can imagine the protein now as being a very snazzy origami bird. Like this:

The Golgi then calls upon another vesicle...

Step 5:
Hand it to another vesicle...

Now, when covering the digestive system in GCSE, you should hopefully have heard of enzymes and the fact that they are proteins. If our protein was an extracellular enzyme, for example, then the vesicle would carry it to the cell's surface and release it. If the cell, in which all this has been happening, was part of the small intestine wall, for example, then the protein might be a lipase enzyme or a protease enzyme and be excreted by the cell to digest your dinner, and therefore help gather useful substances for all the other cells in your body... Incredible, isn't it?