Principles of Cellular Respiration
November 5th, 2013
Students in a Biology 1 lab class constructed an experiment on Cellular Respiration by investigating the effects of temperature on crickets’ metabolic rate. By following the following procedures out of the Lab Manual, the students were able to find an almost accurate representation of the crickets’ cellular respiration rate under various temperatures in order to produce CO2. The crickets used in the experiment provided a prime example of how ectothermic critters use heat as their source of energy to metabolize their food.
A perpetual source of energy is a vital role in all organisms to preform their metabolic functions. The precise process in which extracts energy from the following organic nutrients: proteins, carbohydrates, and fats are expended as fuel to form adenosine triphosphate (ATP). This process is cellular respiration, which is also referred to as aerobic respiration involves both aerobic and anaerobic respiration that occurs in the mitochondria of a cell. There are three stages of cellular respiration which can also be considered, energy harvesting. The first stage of cellular respiration is glycolysis, and also means, “sugar splitting.” Although, there isn’t much energy or ATP produced from this stage. The main purpose of glucose is to take one single glucose molecule and break it down into two molecules of a pyruvic acid, which is a three-carbon molecule. If the cell is not equipped with oxygen, then the fermentation process is engaged. In the fermentation process the pyruvate molecule is converted into ethanol or lactic acid. The fermentation process wasn’t administered in the experiment since the crickets required air to breathe.
In order for the Krebs cycle or Citric Acid Cycle, which is the second stage of cellular respiration to occur it needs to acquire ATP and NADH. Within this stage of cellular respiration, the pyruvate molecules convert into acetyl CoA. This happens when the carbon dioxide exits the pyruvate and the NAD+ turns into NADH. Citrate is then created when the acetyl CoA merges with the oxaloacetate from the first cycle of the citric acid cycle and turning the citrate into isocitrate. Shortly after that happens, the isocitrate becomes oxidized to succinyl CoA, leaving the products of carbon dioxide and NADH2+. Then the succinyl CoA release the coenzyme A and phosphorylates the ADP into ATP. The succinate is then oxidized to create fumarate, which then converts the FAD into FADH2. The fumarate is then hydrolyzed to create malate. Finally, the malate is then oxidized to create oxaloacetate, which reduces the NAD+ into NADH2+. This cycle process continues for a total of two cycles to produce six NADH2+, two FADH2, and two ATP.
The third and final stage of the cellular respiration process is the electron transport chain (ETC). This is where most of the ATP is produced and is only administered when oxygen is available. The electron transport chain is a sequence of molecules, which are located in the mitochondrial inner membrane. Just before attaining the ETC, NADH and FADH2 the electron carriers become oxidized by other molecules in the chain. By accepting the previous electrons in the citric acid cycle reduces both, the NADH and FADH2 of those electron carriers. The final electron acceptor in the electron transport chain is oxygen. The movement of the electrons within the ETC delivers an adequate amount of energy to power the movement of hydrogen ions proceeding to the three ETC protein complexes, from the middle of the mitochondria to the outer area. These ions move down the concentration and charge their gradient, which moves them back into the middle of the mitochondria and through the ATP synthase. The ATP synthase drives the production of ATP from the ADP and phosphate....
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