A large number of proteins made by the ribosomes get modified in .

Options

A. Lysosomes.
B. Trans face of Golgi apparatus.
C. Cisternae of Golgi apparatus.
D. Smooth endoplasmic reticulum .

Answer

**Step-by-Step Solution:**

1. **Understanding Protein Synthesis**: Proteins are synthesized by ribosomes, which can be found either free in the cytoplasm or attached to the rough endoplasmic reticulum (RER). The rough ER is specifically involved in the synthesis of proteins that are to be secreted or sent to lysosomes or the plasma membrane.

2. **Transport to the Golgi Apparatus**: After synthesis, the newly formed proteins are packaged into vesicles and transported to the Golgi apparatus. The Golgi apparatus is a cellular organelle that plays a crucial role in modifying, sorting, and packaging proteins for secretion or delivery to other organelles.

3. **Structure of the Golgi Apparatus**: The Golgi apparatus consists of a series of flattened, membrane-bound sacs known as cisternae. It has a distinct polarity with a 'cis' face (the receiving side) and a 'trans' face (the shipping side).

4. **Entry at the Cis Face**: Proteins from the rough endoplasmic reticulum enter the Golgi apparatus at the cis face. This phase is convex and oriented towards the nucleus, where vesicles from the ER fuse with the Golgi.

5. **Modification of Proteins**: As proteins move through the Golgi apparatus from the cis face to the trans face, they undergo various modifications. These modifications can include glycosylation (addition of sugar molecules), phosphorylation, and other chemical changes that are essential for their final functional forms.

6. **Exit at the Trans Face**: Once the proteins have been modified, they exit the Golgi apparatus from the trans face, which is concave and oriented away from the nucleus. The modified proteins are then packaged into vesicles for transport to their final destinations within or outside the cell.

7. **Final Answer**: Therefore, the correct answer to the question is that a large number of proteins made by ribosomes get modified in the **cisternae of the Golgi apparatus**.

---