Energy Currency, the Science of ATP
Known as the ‘energy currency of life,’ ATP can store and transport the energy we need to do just about everything that we do. Essentially all metabolic functions of living cells require energy for operation and obtain it directly from stored ATP. Every cell in the human body produces ATP as part of its metabolic function. In fact 95% of the ATP produced in the body is produced in the mitochondria. For this reason, ATP is often referred to as the power house of the cell, although ATP has several other equally important functions as well.
All molecules contain energy, stored in the molecular structure itself. A portion of that energy can be used to do work. This is called free energy. Oxidation of a molecule results in the release of free energy. Complete combustion (burning) of organic molecules, eg, releases all of the available free energy as heat. Reduction of a molecule requires an input of energy. Energy can be transferred from one molecule to another by enzymes.
The molecules that are converted by enzymes, that is, the reactants, are called substrates. Nutrients are organic molecules that are ultimately derived from food sources. They start off as fats, carbohydrates, and proteins. Enzymes such as pancreatic enzymes example in intermediate metabolism oxidize nutrient molecules to a form that can be converted to energy by mitochondria. Fats, carbohydrates and proteins are broken down to individual fatty acids, simple sugars and amino acids.
Phosphate Groups and Energy?
These molecules can transport energy because phosphate bonds contain a lot of potential energy, which is released when they are broken.
Energy is stored in the covalent bonds between phosphates, with the greatest amount of energy.
Humans /mammals Eat Energy Originally Obtained by Plants and such
Humans, cannot make organic compounds from inorganic sources. We must obtain useful compounds from organic sources by consuming plants and animals ect. How Is ATP Actually Made? ATP is produced by humans during a catabolic process known as cellular respiration. Because of this fact one would believe we could never become deficient in ATP, but this is not true, and when this deficiency occurs a cascade of problems will be evident Cachexia in late stage cancer patients, heart issues, just to name a few.
In cellular respiration food molecules are broken down and the released energy is transformed into ATP. Organisms catabolize (break down) carbohydrates, most commonly glucose, to ultimately make ATP and use if for anabolic cellular reactions.
Glucose catabolized by through the processes of aerobic respiration and anaerobic fermentation.
Aerobic respiration utilizes glycolysis, synthesis of acetyl-CoA, Krebs cycle, and electron transport chain; the end result being the complete breakdown of glucose into carbon dioxide and water. Through these catabolic reactions up to 34 molecules of ATP can be made from every molecule of glucose. Oxygen is a vital component of this highly efficient process, hence the name ‘aerobic respiration’ Where Is ATP Made? In eukaryotic cells, complex cells that possess a nucleus, ATP is synthesized in the tiny energy factories called mitochondria.