Phosphorus is important for the synthesis of which of the following?

Phosphorus plays a crucial role in the synthesis of DNA, which is the molecule that carries genetic information in all living organisms. Its presence is essential because it forms part of the backbone of the DNA structure, specifically in the phosphate groups that connect the sugar molecules in the DNA strand. This structural integrity is vital for DNA replication and transcription processes, enabling the proper functioning and reproduction of cells.

While phosphorus is also involved in the synthesis of other biological molecules, such as ATP (adenosine triphosphate), which is important for energy transfer in cells, the question focuses specifically on synthesis in relation to DNA. The other options, while important macromolecules in biology, do not have phosphorus as a primary component in their structural makeup. For example, proteins are made from amino acids, and although amino acids contain nitrogen and sometimes sulfur, phosphorus is not a key element in their structure. Similarly, chlorophyll is predominantly composed of carbon, hydrogen, nitrogen, and magnesium, with no direct role of phosphorus in its synthesis. Therefore, the assertion that phosphorus is essential for DNA synthesis is clearly the most accurate in this context.