Final answer:
Living cells gather and use energy based on the laws of thermodynamics. They obtain energy from external sources and use it for various cellular processes. The flow of energy in living systems is described by bioenergetics and metabolism.
Step-by-step explanation:
Living cells gather and use energy according to the laws of thermodynamics, which govern the transfer of energy in all systems. In biological systems, energy is obtained from external sources such as the sun or energy-storing molecules.
Cells utilize this energy for processes like synthesis and breakdown of molecules, transport of molecules, and movement. The energy flow in living systems is described by bioenergetics, and all the chemical reactions that take place inside cells are referred to as metabolism.