Final answer:
The organic compound used for stored chemical energy and may contain a phosphate group, along with carbon, hydrogen, and oxygen is a lipid. While carbohydrates like starch are important energy sources, they do not typically contain phosphate groups. Lipids serve many functions including energy storage, with some containing phosphate groups in structures like phospholipids.
Step-by-step explanation:
Biological Macromolecules and Stored Chemical Energy
The organic compound used for stored chemical energy that contains carbon, hydrogen, oxygen, and sometimes a phosphate group is a lipid. Lipids are one of the four major classes of biological macromolecules, which also include carbohydrates, proteins, and nucleic acids. Each of these macromolecules serves important functions in living organisms. Notably, carbohydrates like starch are primary energy sources and are composed solely of carbon, hydrogen, and oxygen, without phosphate groups. Proteins are made up of amino acids and serve various functions including catalysis of biochemical reactions, while nucleic acids like DNA and RNA are responsible for genetic information storage and transmission.
Lipids, on the other hand, serve several key roles in organisms, such as energy storage, insulation, and forming cellular membranes. Some lipids, like phospholipids, contain phosphate groups and are critical components of cell membranes, where they contribute to membrane structure and function. Others, like triglycerides, store energy more efficiently than carbohydrates and do not contain phosphate groups. Therefore, in the context of the question, lipids are the correct answer as they are the organic compounds used for chemical energy storage that may contain phosphate groups in addition to carbon, hydrogen, and oxygen.