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Where does the energy that makes life possible come from? Humans obtain energy from three classes of fuel molecules: carbohydrates, lipids, and proteins.
- Cell Metabolism
Catabolic pathways involve the breakdown of nutrient...
- Cell Metabolism
Food energy is chemical energy that animals (including humans) derive from their food to sustain their metabolism, including their muscular activity. [ 1 ] Most animals derive most of their energy from aerobic respiration , namely combining the carbohydrates , fats , and proteins with oxygen from air or dissolved in water . [ 2 ]
In food and components of the human body, potential energy resides in the chemical bonds of specific molecules such as carbohydrates, fats, proteins, and alcohol. This potential energy is converted into kinetic energy in the body, driving many body functions ranging from muscle and nerve function to driving the synthesis of body protein for growth.
Human nutrition is the process by which substances in food are transformed into body tissues and provide energy for the full range of physical and mental activities that make up human life. Foods supply nutrients that are critical for human growth.
10 Ιαν 2016 · The body uses food to (1) operate organs, (2) maintain a constant temperature by using some of the heat that is generated by operating the organs (while the rest is rejected), (3) do external work, (4) build a stored energy supply (fat) for later needs, (5) grow to adulthood, and (6) help the fetus grow during pregnancy and then nurse infants.
As we have just seen, cells require a constant supply of energy to generate and maintain the biological order that keeps them alive. This energy is derived from the chemical bond energy in food molecules, which thereby serve as fuel for cells.
The usable energy in food is measured in units called kilocalories or, simply, calories. About two-thirds of the energy the body uses goes to keeping body temperature constant, repairing internal organs and skin, keeping the heart beating and lungs breathing, and ensuring the proper chemical balance inside and outside the body's cells.
