Which of the following statements regarding mitochondrial membrane is NOT correct ?

Options

A. The inner membrane is highly convoluted forming a series of infoldings
B. The outer membrane resembles a sieve
C. The outer membrane is permeable to all kinds of molecules
D. The enzymes of the electron transfer chain are embedded in the outer membrane

Answer

To determine which statement regarding mitochondrial membranes is NOT correct, we will analyze each statement provided:

1. **Statement 1**: "The inner membrane is highly convoluted forming a series of infoldings."
- This statement is correct. The inner mitochondrial membrane has many infoldings known as cristae, which increase the surface area for biochemical reactions.

2. **Statement 2**: "The outer membrane represents a sieve."
- This statement is also correct. The outer membrane of the mitochondria is indeed sieve-like, allowing the passage of small molecules and ions.

3. **Statement 3**: "The outer membrane is permeable to all kinds of molecules."
- This statement is correct as well. The outer membrane is relatively permeable, allowing various molecules to pass through freely.

4. **Statement 4**: "The enzymes of the electron transfer chain are embedded in the outer membrane."
- This statement is NOT correct. The enzymes of the electron transport chain are located in the inner mitochondrial membrane, not the outer membrane.

Based on this analysis, the statement that is NOT correct is **Statement 4**.

### Summary of the Solution:
- Statement 1: Correct
- Statement 2: Correct
- Statement 3: Correct
- Statement 4: NOT Correct (this is the answer)