The Ways in Which Organisms Use ATP

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The Ways in Which Organisms Use ATP

        ATP, the standard abbreviation of Adenosine-5’-triphosphate is a multifunctional nucleotide used in cells as a coenzyme, and can be best summarised as the standard energy currency universal to all organisms, and as such is utilised in metabolic (and other) processes throughout the cells of organisms, and is highly adapted to its function therein due to its high instability in aqueous solutions (eg tissue fluid) due to its easily hydrolysable phosphoannhydride bonds which when broken release a proportionally huge amount of energy.

        ATP is required during the contraction of skeletal muscle. ADP is released by the myosin head, this allows it to change shape thereby pulling the actin filament across itself. In order to detach the myosin molecule (for it to bind to a myosin binding site further along the actin) ATP binds to the myosin head, where it is hydrolysed to release ADP (which remains on the head) and inorganic phosphate. The energy released allows the myosin head to resume its normal position prior to the release of its ADP molecule, ready to bind further along the actin filament. Furthermore, ATP is utilised elsewhere within the same process, as it is used by carrier proteins on the membrane of the sarcoplasmic reticulum as a source of energy for the active transport of Ca2+ ions into the sarcoplasmic reticulum. It is when these calcium ions are secreted that the troponin C subunit allows the tropomyosin to reveal the myosin binding site on the actin filament ready for muscle contraction.

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        Whilst ATP is one of the main products of respiration, it is interesting to note that within its first stage, glycolysis, 2 ATP molecules are actually used initially in order to phosphorylate the glucose molecule, forming phosphorylated glucose. This activates the molecule allowing a series of reactions to occur, first by splitting into 2 glycerate-3-phosphate molecules and then producing 2 NADH molecules and 4 ATP molecules in total (leaving 2 pyruvate molecules for the link reaction), with a net gain of 2 ATP molecules. It is this latter point that is most significant when considering anaerobic respiration for it ...

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A thorough and well structured report, which could be improved by: 1) The addition of references 2 Some brief explanations of key terms, processes and molecule roles 3)Attention to formatting 4)Clarification of exactly how it is that ATP supplies the energy for metabolic processes, in terms of energy release during bond formation