Which structure is primarily involved in the modification and sorting of proteins and lipids?

Which structure is primarily involved in the modification and sorting of proteins and lipids?

• A. Mitochondria
• B. Rough ER
• C. Golgi apparatus
• D. Nucleus

Answer: (C)

The Golgi apparatus is the primary structure responsible for the modification and sorting of proteins and lipids within the cell. It functions as a processing center where proteins and lipids received from the endoplasmic reticulum undergo further modifications, such as glycosylation (addition of sugar molecules) and phosphorylation (addition of phosphate groups). After these modifications, the Golgi apparatus sorts and packages these molecules into vesicles, directing them to their appropriate destinations—either within the cell, to the plasma membrane, or outside the cell through secretion. This sorting capability is vital for ensuring that proteins and lipids reach their correct locations to perform their functions properly, which is essential for maintaining cellular organization and function. The other structures listed have different roles: mitochondria are primarily involved in energy production, the rough endoplasmic reticulum is responsible for the synthesis of proteins (particularly those destined for secretion or for use in the cell membrane), and the nucleus contains genetic material and is responsible for transcription and regulation of gene expression, but does not directly modify or sort proteins and lipids in the way the Golgi apparatus does.

The Golgi apparatus is the primary structure responsible for the modification and sorting of proteins and lipids within the cell. It functions as a processing center where proteins and lipids received from the endoplasmic reticulum undergo further modifications, such as glycosylation (addition of sugar molecules) and phosphorylation (addition of phosphate groups).

After these modifications, the Golgi apparatus sorts and packages these molecules into vesicles, directing them to their appropriate destinations—either within the cell, to the plasma membrane, or outside the cell through secretion. This sorting capability is vital for ensuring that proteins and lipids reach their correct locations to perform their functions properly, which is essential for maintaining cellular organization and function.

The other structures listed have different roles: mitochondria are primarily involved in energy production, the rough endoplasmic reticulum is responsible for the synthesis of proteins (particularly those destined for secretion or for use in the cell membrane), and the nucleus contains genetic material and is responsible for transcription and regulation of gene expression, but does not directly modify or sort proteins and lipids in the way the Golgi apparatus does.