The cortex layer of an endospore which helps dehydrate the core by drawing water away from it during the sporulation process is composed largely of what type of macromolecule
The correct answer and explanation is:
Correct Answer: Peptidoglycan
Explanation (300 words):
The cortex layer of an endospore plays a crucial role in the development and survival of the bacterial spore. This layer is located between the inner membrane and the outer coat of the endospore and is composed largely of peptidoglycan, a macromolecule made of sugars and amino acids.
Peptidoglycan is a vital component in bacterial cell walls, but in endospores, it is uniquely modified. The peptidoglycan in the cortex is less cross-linked than that found in vegetative bacterial cells, giving it special properties. Its main function during sporulation (the process of endospore formation) is to dehydrate the core, which helps the spore become highly resistant to environmental stresses such as heat, radiation, chemicals, and desiccation.
Here’s how this works: as the endospore matures, the cortex draws water out of the core by osmosis. The lower water content in the core contributes to enzymatic inactivity and DNA stability, which is critical for the long-term preservation of the cell’s genetic material. The peptidoglycan structure acts as a molecular sieve, regulating water movement and maintaining the dry, gel-like state of the spore core.
The dehydration of the core, facilitated by the cortex’s peptidoglycan, also enables the accumulation of calcium dipicolinate (Ca-DPA), a compound that further stabilizes proteins and nucleic acids inside the spore. Together, these structural and chemical changes help the endospore remain dormant and resistant for extended periods, even under extreme conditions.
In summary, the cortex of the endospore is composed largely of modified peptidoglycan, and its key function is to help dehydrate the core during sporulation, which is essential for the durability and longevity of the endospore.