Final answer:
Energy in biological systems can be absorbed as radiant energy or used to synthesize essential compounds like glucose. It is ultimately converted into ATP, which powers various cellular functions.
Step-by-step explanation:
Energy can be absorbed as radiant energy or used to synthesize compounds. In biological systems, plants absorb solar energy to form glucose through photosynthesis, which is then used to make other carbohydrates, lipids, and proteins. Animals obtain energy by consuming plants or other animals, whereby they digest the chemical energy stored in carbohydrates, fats, and proteins. Within the cells, this energy is transformed into ATP (Adenosine triphosphate), an easily accessible form of energy used by cells to do work, such as building complex molecules, transporting materials, and creating motion.
The flow of energy through ecosystems is depicted in food-web diagrams, showcasing how autotrophs, like plants, harness light or chemical energy, while heterotrophs gain energy through consumption. Chemical energy within organic molecules is transferred and transformed into ATP molecules through cellular reactions, facilitating various forms of cellular work essential for life.