The peptidoglycan molecule is responsible for the:

• A. Entry and exit of molecules into and from the cell.
• B. Flexibility of the cytoplasmic membrane.
• C. Motility of the bacterial cell.
• D. Genetic characteristics of the bacterial cell.
• E. Semi-rigid cell wall structure of prokaryotes.

Answer: (E)

Verified step by step guidance

1. Understand that peptidoglycan is a polymer that forms a mesh-like layer outside the plasma membrane of most bacteria, forming the cell wall.
2. Recognize that the primary function of peptidoglycan is to provide structural support and shape to the bacterial cell, making it semi-rigid.
3. Consider the options given: entry and exit of molecules, flexibility of the cytoplasmic membrane, motility, and genetic characteristics. None of these are directly related to the structural role of peptidoglycan.
4. Identify that the semi-rigid cell wall structure is crucial for maintaining the integrity and shape of prokaryotic cells, which is the role of peptidoglycan.
5. Conclude that the correct answer is the semi-rigid cell wall structure of prokaryotes, as this directly relates to the function of peptidoglycan.