Energy Transfer



Livingcells are required to work continuously in order to ensure that theystay alive, reproduce, and grow. Processes that lead to the growth,development, and reproduction of animal cells require an adequatesupply of energy. The principles of bioenergetics explain how cellsacquire, process, and utilize energy sources in order to carry outall work that facilitates their growth and reproduction (Clark,2012). The first principle holds that animal cells require energy todo their work. One of the most important tasks that cells use energyto carry out is the generation and the maintenance of the highlyordered structure, which is accomplished through the process ofbiosynthesis of different macromolecules. Other tasks that requireenergy include the generation of all types of movements, homeostasis(including the generation of concentration as well as electricalgradients across the membranes and the maintenance of the bodytemperature), and generation of light in a few animal cells.

Theuse of energy in animal cells follows the basic laws ofthermodynamics. This implies that energy that the energy utilized inthe biological systems cannot be created or destroyed. In addition,the process of conversion of energy from a given form to another isnever 100 %, which means that part of the energy gets lost (Clark,2012). Free energy, which is the force that is available to carry outsome work at a constant pressure and temperature, also plays acritical role in the processes that occur within the cells. Enzymesplay the role of speeding up reactions that are thermodynamicallyfavorable.

Adenosinetriphosphate (ATP) is considered as the universal currency for thebiological energy. A molecule of ATP is stable at the pH 7 and enzymecatalysis is required to facilitate its hydrolysis (Clark, 2012). ATPmolecules supply energy to different biological processes through agroup transfer that involves the donation of Pi, PPi, and AMP inorder to form covalent intermediates. Energy that is provided throughthe group transfer activates the substrate. The process ofdecomposition of ATP into ADP that leads to the release of energy iscatalyzed by enzymes (such as adenylpyrophosphatase,triphosphatase,and ATP monophosphatase)known as ATPases.

Biologicalenergy is released following the transfer of electrons through redoxreactions. Redox reactions occur when elections are transferred froma reductant (a low affinity carrier) to an oxidant (a high affinitycarrier). Universal carriers (including NAD+,NADP+,and FAD) transfer electrons from the process of oxidation ofdifferent substrates (Clark, 2012). NADP and NAD are able to donateor accept one hydrogen ion, while FAD has the capacity to donate oraccept two electrons. In overall, bioenergetics is produced through astepwise flow of electron, which is made possible by electroncarriers that have an increasing level of electron potential.

Chemicalenergy is transferred from glucose (unusable form) to ATP (usableform) in animal cells. The process is different in photosynthesizingcells, where energy is transformed from light into compounds (such asglucose) that are rich in energy. This process occurs through theanabolic pathways. Photosynthesizing cells are able to produce andstore energy in the form of ATP.

Inconclusion, the principles of bioenergetics describe the processesinvolved in the transfer and utilization of energy in the livingcells. Plant cells are different from animal cells in that they areable to transfer energy from light to different compounds. However,photosynthesizing cells are also able to break down ATP using thesame type of enzymes and universal carriers as the animal cells inorder to release some energy for different functions, such as growth,reproduction, and germination.


Clark,K. (2012). Bioenergetics.Rijeka: In Tech.