The some peptide hormone will show variation in response to different cells because

Options

A. different target cells have different sets of genes
B. a target cell's response is determined by the components of its signal transduction pathways
C. the circulatory system regulates response to hormone by routing the hormone to specific targets
D. the hormone is chemically altered in different ways as it travels through the circulatory system

Answer

To solve the question regarding why some peptide hormones show variation in response to different cells, we can analyze the options provided and determine the correct reasoning step by step.

### Step-by-Step Solution:

1. **Understanding Peptide Hormones**:
- Peptide hormones are signaling molecules that bind to specific receptors on target cells to elicit a response.

2. **Evaluating Option 1**:
- The first option states that "different target cells have different sets of genes."
- This statement is incorrect because all cells in the human body contain the same set of genes. The difference lies in which genes are expressed in each cell type.

**Hint**: Remember that while all cells have the same genetic material, gene expression varies among different cell types.

3. **Evaluating Option 2**:
- The second option claims that "the target cell's response is determined by the components of its signal transduction pathway."
- This statement is correct. Different cells may have different signaling pathways and receptors, which lead to varied responses to the same hormone.

**Hint**: Focus on how signal transduction pathways can differ between cell types and how this affects hormone response.

4. **Evaluating Option 3**:
- The third option suggests that "the circulatory system regulates response to hormones by routing them to specific targets."
- This statement is misleading. While hormones travel through the bloodstream, they do not specifically target cells; rather, they affect any cell with the appropriate receptors.

**Hint**: Consider how hormones circulate in the body and the role of receptors in determining the target cells.

5. **Evaluating Option 4**:
- The fourth option states that "hormones are chemically altered in different ways as they travel through the circulatory system."
- This statement is incorrect. Hormones remain unchanged as they circulate in the bloodstream until they bind to their receptors.

**Hint**: Think about the stability of hormones in circulation and their unchanged nature until they interact with target cells.

6. **Conclusion**:
- After evaluating all options, the only correct statement is option 2: "the target cell's response is determined by the components of its signal transduction pathway."

### Final Answer:
The correct answer is option 2.

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