Which of the following is incorrect

Options

A. Plasmalemma is the outer cell membrane
B. Membrane surrounding an organelle is called subcellular
membrane
C. Membranes forming endoplasmic reticulum are biomembranes
D. Prokaryotic cells have subcellular membranes

Answer

To solve the question "Which of the following is incorrect?", we will analyze each of the four statements provided.

### Step-by-Step Solution:

1. **Analyze the First Statement:**
- **Statement:** "Plasma lemma is the outer cell membrane."
- **Evaluation:** This statement is correct. The plasma lemma, also known as the plasma membrane, is indeed the outer membrane of the cell that separates the interior of the cell from the external environment.

2. **Analyze the Second Statement:**
- **Statement:** "Membrane surrounding an organelle is called subcellular membrane."
- **Evaluation:** This statement is also correct. In eukaryotic cells, the membranes that surround organelles (like the nucleus, mitochondria, etc.) are referred to as subcellular membranes.

3. **Analyze the Third Statement:**
- **Statement:** "Membranes forming endoplasmic reticulum are biomembranes."
- **Evaluation:** This statement is correct as well. The membranes that make up the endoplasmic reticulum (ER) are indeed biomembranes, which are composed of lipid bilayers.

4. **Analyze the Fourth Statement:**
- **Statement:** "Prokaryotic cells have subcellular membranes."
- **Evaluation:** This statement is incorrect. Prokaryotic cells, such as bacteria, do not have membrane-bound organelles. Instead, their organelles are non-membrane bound, meaning they lack subcellular membranes.

### Conclusion:
The incorrect statement among the options is the fourth one: "Prokaryotic cells have subcellular membranes." Therefore, the answer is **D**.

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