The Great Metabolic Race

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The Great Metabolic Race

Metabolism comprises of a vital set of biochemical reactions that all living organisms require to sustain life. For a marathon runner, their physiological response to strenuous exercise depletes both their fats and carbohydrate storage in order to supply energy in the form of Adenosine Triphosphate (ATP). ATP is the energy form that the human body uses for biological processes such as movement and synthesis of biomacromolecules. In regards to running a marathon, the athlete is capable of using a combination of both anaerobic and aerobic pathways, but these different systems predominate at different intervals in order to increase the energy allowed for the muscles.

At the beginning of the race, the athlete’s
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One of the most significant reactions in Glycolysis is reaction one which involves the phosphorylation of glucose to form glucose-6-phosphate. Through the transfer of the hydrolysis of ATP, this supplies energy for the reaction and makes it essentially irreversible, having a negative free energy change, which allows for a spontaneous reaction in cells. Although the preparatory phase is energy consuming and uses up 2 ATP, the pay off phase synthesizes 4 molecules of ATP, with the transfer of 4e- via 2 hydride ions to 2 molecules of NAD+. Therefore, a net gain of 2 ATP is achieved through the glycolytic pathway alone. Following the glycolytic pathway, due to the absence of oxygen, as oxygen cannot be supplied fast enough to undergo aerobic respiration, the athlete will instead, undergo lactic acid fermentation. Lactic acid fermentation involves pyruvate that is formed from the glycolytic pathway to be reduced to lactate, with the aid of the enzyme, lactate dehydrogenase, while the coenzyme Nicotinamide Adenine Dinucleotide (NADH) is oxidised to NAD+. The product NAD+ then re-enters the glycolytic pathway in order to produce 2 ATP. This process of lactic acid fermentation produces 2 ATP for each cycle, and thus, rapidly supplies the body with a small amount of energy. However, with the buildup of lactic acid in the body, the athlete will eventually encounter the feeling of discomfort as this accumulation of lactate causes the body to
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