Essay on Aerobic Cellular Respiration

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Aerobic Cellular Respiration Humans, and all animals, use adenosine triphosphate (ATP) as the main energy source in cells. The authors of Biological Science 5th edition said that “In general, a cell contains only enough ATP [adenosine triphosphate] to last from 30 seconds to a few minutes”. It is that way “Because it has such high potential energy, ATP is unstable and is not stored”. They also state that “In an average second, a typical cell in your body uses an average of 10 million ATP molecules and synthesizes [makes] just as many”. In the human body trillions of cells exist. The average human body uses and makes 10,000,000,000,000,000 molecules of ATP every second. In one minute the human body uses 600,000,000,000,000,000…show more content…
The second reaction uses a different enzyme called phosphoglucose isomerase, which converts glucose-6-phosphate (C6H1305PO4) to fructose-6-phosphate (C6H13O5PO4). The structure changes but the chemical formula does not. Then in the next reaction, (#3), which is catalyzed by the protein phosphofructokinase, the fructose-6-phosphate (C6H13O5PO4), gains another phosphate group to become fructose-1,6-biphosphate. Instead of having just one inorganic phosphate group (HPO42-), now it has two. This increases the potential energy of the molecule. This step did cost another ATP molecule. The fourth reaction is catalyzed by the protein, fructose-bis-phosphate aldolase, that protein splits fructose-1,6-biphosphate, to form two separate 3-carbon sugars one of which is dihydroxyacetone phosphate (DAP). The fifth reaction, which is catalyzed by a protein called triose phosphate isomerase, changes two molecules of DAP into two molecules of G3P (glyceraldehyde-3-phosphate). The next reaction, number six, is catalyzed by the protein glyceraldehyde-3-phosphate dehydrogenase, “A two-step reaction . . . that first oxidizes G3P [by] using the [Nicotinamide adenine dinucleotide] NAD+ coenzyme [chemical formula is C21H27N7O14P2] to produce . . . [NADH, NADH is a coenzyme, whose chemical formula is C21H28N7O14P2]. Energy from this reaction is used to attach . . . [2] Pi [HPO4- groups] to the oxidized product to form [2]
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