What is the primary function of the Golgi apparatus?

The primary function of the Golgi apparatus is to package proteins for secretion. This organelle plays a crucial role in the processing and sorting of proteins and lipids that have been synthesized in the endoplasmic reticulum (ER). Once the proteins are manufactured in the rough ER, they are transported to the Golgi apparatus, where they undergo further modifications, such as glycosylation (adding sugar groups), and then are packaged into vesicles.

These vesicles can either be directed to lysosomes, where they perform various functions within the cell, or they are packaged for secretion outside the cell. This function is vital for cellular communication and the overall metabolic activity of the organism, as many proteins serve critical roles outside the cell, including enzymes, hormones, and structural components of tissues.

The other options describe functions that involve different organelles: producing ATP is primarily the role of mitochondria, storing nutrients falls under the duties of various storage organelles (like vacuoles or vesicles), and carbohydrate synthesis typically involves ribosomes and the endoplasmic reticulum rather than the Golgi apparatus. This demonstrates the Golgi apparatus's distinct function within the cell's machinery.