Final answer:
Proteins and nucleic acids are the molecules that primarily control the biochemical reactions occurring within organisms, making them key components of life's processes. Both play essential roles in the regulation of cellular functions, from genetic information storage to catalyzing reactions.
Step-by-step explanation:
The molecules which make up organisms and control the biochemical reactions that occur within them are proteins and nucleic acids. While carbohydrates and lipids are crucial for providing energy and making up cell membranes, respectively, it is proteins and nucleic acids that play the central roles in the regulation and execution of cellular functions.
Proteins are responsible for a plethora of functions within organisms, including acting as enzymes to catalyze chemical reactions, as structural components, signal molecules, and transporters. Nucleic acids, such as DNA and RNA, are vital for storing genetic information and are also crucial in the process of protein synthesis. In a broader view, the study of these macromolecules and their roles within living organisms is encompassed by the field of Biochemistry, a discipline that deals with the chemical processes and substances which occur within living organisms.