Select incorrect statement regarding cell envelope in prokaryotes.

Options

A. Most prokaryotic cells have a chemically complex cell envelope.
B. Each layer of the envelope performs same function
C. It has outermost glycocalyx followed by the cell wall and then the plasma membrane.
D. The cell envelope consists of a tightly bound there layered structure

Answer

To solve the question regarding the incorrect statement about the cell envelope in prokaryotes, we can follow these steps:

### Step 1: Understand the Structure of the Cell Envelope in Prokaryotes
Prokaryotic cells, such as bacteria, have a cell envelope that typically consists of three main layers:
- **Plasma Membrane**: The innermost layer that regulates the entry and exit of substances.
- **Cell Wall**: The middle layer, which provides structural support and is primarily composed of peptidoglycan. The thickness of the cell wall varies between Gram-positive and Gram-negative bacteria.
- **Glycocalyx (Capsule)**: The outermost layer, which can be a capsule or slime layer that helps in protection and attachment.

### Step 2: Analyze Each Statement
Now, let's evaluate each of the provided statements regarding the cell envelope:

1. **Most prokaryotic cells have a complex cell envelope.**
- This statement is **correct**. Prokaryotic cells, especially bacteria, often have a complex structure in their cell envelope.

2. **Each layer of the envelope performs the same functions.**
- This statement is **incorrect**. Each layer of the cell envelope has distinct functions; for example, the plasma membrane is involved in transport, the cell wall provides structural integrity, and the glycocalyx aids in protection and virulence.

3. **It has outermost glycocalyx followed by cell wall and plasma membrane.**
- This statement is **correct**. The typical arrangement of the layers is indeed the glycocalyx on the outside, followed by the cell wall, and then the plasma membrane.

4. **The cell envelope consists of a tightly bound three-layer structure.**
- This statement is **correct**. The cell envelope is indeed a tightly bound structure made up of these three layers.

### Step 3: Identify the Incorrect Statement
From the analysis, the statement that is incorrect is:
**"Each layer of the envelope performs the same functions."**

### Conclusion
The incorrect statement regarding the cell envelope in prokaryotes is that each layer performs the same functions.

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