Steriod hormones easily pass through the plasma membrane by simple diffusion because they

Options

A. Are lipid soluble
B. Are water soluble
C. Enter through pores
D. Contian carbon and hydrogen.

Answer

**Step-by-Step Solution:**

1. **Understanding Steroid Hormones**:
- Steroid hormones are a class of hormones that include glucocorticoids, mineralocorticoids, and progesterone. They are derived from cholesterol and have a specific chemical structure.

2. **Chemical Composition**:
- Steroid hormones are characterized by their hydrophobic (water-repelling) nature. This means they do not mix well with water but are soluble in lipids (fats).

3. **Plasma Membrane Structure**:
- The plasma membrane of cells is composed of a lipid bilayer, which consists of phospholipids. This structure allows lipid-soluble substances to pass through more easily compared to water-soluble substances.

4. **Mechanism of Diffusion**:
- Steroid hormones pass through the plasma membrane by a process called simple diffusion. This process does not require energy and occurs along the concentration gradient (from an area of higher concentration to an area of lower concentration).

5. **Evaluating Options**:
- Now, let's evaluate the options provided in the question:
- **Lipid soluble**: Correct. Steroid hormones are lipid soluble, allowing them to diffuse through the lipid bilayer of the plasma membrane.
- **Water soluble**: Incorrect. Steroid hormones are not water soluble.
- **Enter through pores**: Incorrect. They do not enter through pores; they diffuse directly through the membrane.
- **Contain carbon and hydrogen**: Incorrect. While steroid hormones do contain carbon and hydrogen, this characteristic does not explain their ability to pass through the plasma membrane.

6. **Conclusion**:
- Therefore, the correct answer is that steroid hormones easily pass through the plasma membrane by simple diffusion because they are **lipid soluble**.

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