What type of molecule is responsible for directing the synthesis of all other cellular molecules?

Nucleic acids, primarily DNA and RNA, are the molecules responsible for directing the synthesis of all other cellular molecules, including proteins, which are crucial for cellular structure and function. DNA contains the genetic instructions for the development and functioning of living organisms, encoding the information necessary for making every protein through the processes of transcription and translation.

During transcription, a specific segment of DNA is copied into messenger RNA (mRNA), which then carries the genetic code from the nucleus to the ribosomes, where translation occurs. The ribosomes read the mRNA sequence and assemble amino acids in the correct order to form proteins. This fundamental role of nucleic acids is central to cellular biology, as all aspects of a cell's function depend on the proteins it produces, which are dictated by the genetic information encoded in nucleic acids.

Hormones, while important signaling molecules in the body, do not directly dictate the synthesis of other molecules; instead, they often regulate processes and influence physiological functions. Ribosomes are essential for protein synthesis but are not the molecules that contain genetic information necessary for determining how proteins are made. Cellulose is a structural component of plant cell walls and does not play a role in directing the synthesis of cellular molecules.