Final answer:
Energy, particularly in the form of ATP, is essential for synthesizing new biomolecules, membrane transport, and mechanical work in living organisms, supporting a wide range of cellular and organismal functions.
Step-by-step explanation:
The substance used for the synthesis of new biomolecules, membrane transport, and mechanical work in living organisms is energy, primarily in the form of adenosine triphosphate (ATP). This energy is critical for an array of cellular processes including the synthesis of macromolecules (anabolism), active transportation of materials across cellular membranes, and the contraction of muscle fibers, all of which contribute to movement and growth. ATP's role in energy transfer is akin to a rechargeable battery that powers cellular function.
Energy is harnessed and utilized for tasks such as building complex molecules from smaller ones. This includes not only the synthesis of proteins and nucleic acids but also complex carbohydrates, and lipids. Additionally, ATP provides the energy necessary for primary active transport, receptor-mediated endocytosis, and other cellular activities that contribute to organismal homeostasis.