The endoplasmic reticulum is closely associated with the Golgi apparatus. Synthesized proteins from the RER are released from which part of the Golgi apparatus?

Options

A. Cis face of Golgi apparatus
B. Cisternae
C. Trans face of Golgi apparatus
D. Both (a) and (c)

Answer

To answer the question about where synthesized proteins from the rough endoplasmic reticulum (RER) are released from the Golgi apparatus, we can follow these steps:

### Step 1: Understanding the Structure of the Golgi Apparatus
The Golgi apparatus is a membrane-bound organelle that consists of flattened, sac-like structures called cisternae. It is involved in the processing and packaging of proteins synthesized in the rough endoplasmic reticulum.

**Hint:** Remember that the Golgi apparatus has distinct regions: the cis phase (receiving side) and the trans phase (shipping side).

### Step 2: Identifying the Relationship Between RER and Golgi Apparatus
The rough endoplasmic reticulum (RER) is responsible for synthesizing proteins. These proteins are packaged into transport vesicles that bud off from the RER and move towards the Golgi apparatus.

**Hint:** Think about how proteins move from one organelle to another in the cell.

### Step 3: Understanding the Function of the Golgi Apparatus
Once the transport vesicles reach the Golgi apparatus, they fuse with the cis phase (the side facing the RER) of the Golgi apparatus. Here, the proteins are received and undergo further processing and modification.

**Hint:** The cis phase is where proteins enter the Golgi apparatus, not where they are released.

### Step 4: Identifying the Release Phase
After processing, the proteins are packaged into new vesicles that bud off from the trans phase (the side facing away from the RER) of the Golgi apparatus. This is the phase where proteins are released to be sent to their final destinations, either within the cell or outside of it.

**Hint:** The trans phase is crucial for the export of proteins after they have been modified.

### Conclusion
The synthesized proteins from the rough endoplasmic reticulum are released from the **trans phase** of the Golgi apparatus.

**Final Answer:** Trans phase of the Golgi apparatus.