What does the term "'denature" refer to in molecular biology?

Denature in molecular biology specifically refers to the process where proteins or nucleic acids lose their natural structure due to the breaking of various bonds and interactions that maintain their shape. For proteins, this often involves the unfolding of their three-dimensional structure, which is critical for their function. If a protein denatures, it can no longer perform its biological role effectively. This is often caused by factors such as extreme temperatures, changes in pH, or exposure to certain chemicals.

In the case of nucleic acids, such as DNA, denaturation typically refers to the separation of the two strands of the helix, which happens when exposed to high temperatures or alkaline conditions. This process is fundamental in techniques like PCR (Polymerase Chain Reaction) where denaturation is a key step in amplifying DNA.

The other options focus on unrelated processes, such as the decomposition of organic material, identification of genetic markers, or the isolation of DNA from cells, which do not encapsulate the concept of denaturation in the context of molecular biology.