No, carbohydrates are not added to proteins by the Golgi apparatus. While the Golgi apparatus is crucial for protein modification, it primarily adds carbohydrates to proteins that were initially synthesized in the endoplasmic reticulum (ER).

Here's a breakdown:

* Endoplasmic Reticulum (ER): This organelle is where proteins are initially synthesized. Some proteins will undergo glycosylation, meaning carbohydrates are attached to them.

* Golgi Apparatus: This organelle receives proteins from the ER and further modifies them. It can add, remove, or modify the carbohydrates that were already attached in the ER.

* Glycosylation: This process of adding carbohydrates to proteins is important for several reasons:

* Protein folding: Carbohydrates can help proteins fold correctly and maintain their shape.

* Cellular signaling: Carbohydrates can act as recognition signals for other cells or molecules.

* Protein stability: Carbohydrates can protect proteins from degradation.

So, the Golgi apparatus doesn't add carbohydrates from scratch, but it modifies the existing glycosylation patterns on proteins.