Out mitochondrial membrane resembles bacterial membrane and outer chloroplast membrane in having

Options

A. Selective permeability
B. Single ion channels
C. Porins
D. All the above

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the similarities between the outer mitochondrial membrane, bacterial membrane, and outer chloroplast membrane.

2. **Identifying the Options**: The options provided are:
- A) Selective permeability
- B) Single ion channel
- C) Porous
- D) All of the above

3. **Analyzing the Membranes**:
- The **outer mitochondrial membrane** is known to be a phospholipid bilayer that contains proteins and has a specific structure that allows certain molecules to pass through.
- The **bacterial membrane** is also a phospholipid bilayer, which can be permeable to various substances.
- The **outer chloroplast membrane** shares similar characteristics with both the mitochondrial and bacterial membranes.

4. **Defining 'Porous'**: The term "porous" refers to the ability of a membrane to allow the passage of certain molecules. In this context, it means that the outer mitochondrial membrane, like the bacterial and outer chloroplast membranes, has channels that permit the movement of molecules smaller than 10,000 Daltons.

5. **Evaluating the Options**:
- **Selective permeability**: While all membranes are selectively permeable, this does not specifically highlight the resemblance among the three membranes.
- **Single ion channel**: This is not a characteristic that applies broadly to these membranes.
- **Porous**: This is a defining characteristic that applies to all three membranes, allowing for the passage of small molecules.
- **All of the above**: This option cannot be correct since not all the previous options apply.

6. **Conclusion**: The outer mitochondrial membrane resembles the bacterial membrane and outer chloroplast membrane primarily in being **porous**.

### Final Answer:
The correct answer is **C) Porous**.

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