Health & Social Care Level 3 - Energy

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What is Energy? Energy is defined as the ability to do work. There are two main types of energy: ← Kinetic – the energy of motion. Heat, light, electrical, mechanical and sound are all examples of kinetic energy. ← Potential - stored energy. The energy stored in chemical bonds is an example of potential energy. Laws of Energy The first law of energy states that energy cannot be created or destroyed, but may be converted from one form into another. For example, a chemical to chemical transformation takes place in cellular respiration; muscles need a chemical to kinetic (movement) transformation. Energy may also be stored (potential energy). If any work is done, some starting energy is lost as heat. This includes energy transfer at a cellular level. Therefore, this is not 100% efficient method and, unless the system is continuously topped up with energy input, it will break down. The second law of energy states that all natural processes tend to proceed in a direction which increases the randomness or disorder of the system. The degree of randomness is called entropy. A highly organised structure, such as the human body, has low entropy. Free energy is the energy available to do work under constant temperature and pressure. Systems with low entropy have high levels of free energy. Why does the Human Body need Energy? ← Anabolism: the building up of large molecules from small ones, e.g. protein synthesis from amino acids; DNA replication; polysaccharide synthesis from monosaccharides. Anabolism is essential for growth; repair of cells after injury or disease; renewal of cells when they need replacing; and reproduction ← Movement: muscle contraction, ciliary action, cell division, nerve impulses ← To maintain a steady body temperature and to stay warm ← Active Transport of materials across cell membranes ←
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