At the start of the race, anaerobic pathways are used to provide a quick source of energy. Most of this energy is derived from the catabolism of fats. Since lipids are more reduced than carbohydrates, they are capable of storing more energy per unit weight. Triacylglycerols are the lipids used for energy storage. They are comprised of three fatty acids linked to a glycerol molecule. Triacylglycerols are stored by animals in adipocytes, which collectively make up adipose tissue, and also in the liver.
Mobilisation of triacylglycerols is important in the hours …show more content…
At this stage, roughly 85% of energy is being supplied by carbohydrates. The oxidation of carbohydrates, in particular glucose, is the major source of metabolic energy for most cells. Glycogen is the major glucose storage polymer in animal cells. It consists of chains of glucose residues linked by α-1,4 bonds with branching, linked by α-1,6 bonds, occurring every 8-12 residues. The many non-reducing ends of glycogen may act as a site for the removal of glucose, increasing the speed of breakdown. The enzyme glycogen phosphorylase removes glucose residues until within four residues before a branch point to form glucose-1-phosphate, a potential source for the glycolytic pathway. In order to remove branches, a debranching enzyme is required. This bifunctional enzyme catalyses two successive reactions which remove branches from …show more content…
β-oxidation makes 7NADHs and 7FADH2s while the citric acid cycle produces 24NADHs, 8FADH2s and 8GTPs. This results in a total yield of 106ATPs.
Knowing the yields of ATPs, the amount of ATPs generated per carbon atom can be calculated for each of them. Glucose (6Cs) delivers 5.3ATPs per carbon while palmitic acid (16Cs) produces 6.6ATPs per carbon. This shows that fatty acids are capable of storing more energy per carbon atom than carbohydrates.
In addition to their different structures, as mentioned before, carbohydrates and lipids serve different roles in the generation of energy. Carbohydrates (glycogen mobilisation) serves as a source of quick energy for the muscles, particularly during strenuous activity, while lipids (fatty acids) are the preferred energy source due to their high energy per unit weight. Hence they are used at different timepoints (reasons described at the start, after five minutes and after forty-five