Secretory polypeptide carrying signal peptide is called

Options

A. Peptone
B. Enzyme
C. Preprotein/Proprotein
D. Protein.

Answer

To answer the question "Secretory polypeptide carrying signal peptide is called," we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Understanding the Terms**:
- A secretory polypeptide is a type of protein that is synthesized in the cell and is destined to be secreted outside of the cell.
- A signal peptide is a short peptide sequence that directs the transport of the polypeptide to the secretory pathway.

2. **Role of Signal Peptide**:
- The signal peptide is crucial for the initial targeting of the polypeptide to the endoplasmic reticulum (ER), where it begins its journey to be secreted.

3. **Post-Translational Modifications**:
- After the polypeptide is synthesized, it undergoes post-translational modifications. This process involves the addition of various chemical groups (like phosphate, methyl, acetyl, or carbohydrates) to the protein.
- These modifications are essential for the stability, activity, and function of the protein.

4. **Formation of Pre or Proproteins**:
- The polypeptides that have undergone these modifications are often referred to as preproteins or proproteins. They are in an inactive form until further modifications activate them.

5. **Final Identification**:
- The specific term for a secretory polypeptide that carries a signal peptide and undergoes these modifications is "Rho proteins" or "Re proteins."

### Final Answer:
The secretory polypeptide carrying a signal peptide is called **Rho proteins**.

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