Background: In this experiment, the lab instructor created a catecholase enzyme solution using white potatoes. The potato was the source of enzymes and cofactors in the experiment, as potatoes have sufficient amounts of catecholase and, therefore, cofactors for catecholase. A chilled potato had the peel removed by the instructor and then was chopped into pieces. The potato is peeled so that the brown skin does not interfere with the brown color of the benzoquinone. If this were to occur, the absorbance would seem higher due to the brown potato skin in the solution. The potato was chopped so that the blender did not need to work as hard to break open the cells. The instructor then placed the chopped, peeled potato into a chilled blender. The blender is chilled as heat will speed up the rate of reaction. Cold (chilled) distilled water was then added to the potatoes. This was done to break open the cells of the potato. The catecholase and cofactors are inside the potato cells; water is hypotonic and helps break open cells and release more catecholase. Additionally, tap water contains ions that could be additional cofactors and interfere with the experiment's accuracy. For purposes of this experiment, a slowly progressing reaction is desired, as fast reactions are difficult to observe. The potato and distilled water solution were blended in three ten-second bursts, which released the enzyme from the starch matrix of the potato. The potato was blended in intervals to avoid excessive heat that can activate the enzymes and increase the reaction and absorbance rates. The enzyme solution was then strained through cheesecloth to filter out the starch matrix, which can increase the absorbance rate, as starch and cellulose can also absorb light. The blended potato solution was filled into vials until the vials overflowed. This was done because oxygen is a reactant, and overflowing the vials reduced the amount of oxygen in the vials. Five test tubes were obtained. 1 mL of the enzyme was added to each test tube first. Next, 2 mL of EDTA was added to the EDTA test tube. Similarly, 2 mL of PTU was added to the PTU test tube, and 2 mL of citric acid was added to the citric acid test tube. Finally, 2 mL of dH2O was added to the distilled water test tube, and 4 mL of dH2O was added to the blank test tube. 2 mL of catechol was added last because the reaction will start occurring as soon as it is added. Initial measurements of the test tubes were recorded, and each tube was placed back into the test tube rack to sit for ten minutes. This procedure was repeated after ten minutes. During this ten-minute period, the tubes were all inverted every two minutes to keep contents within the solution evenly mixed and prevent starch buildup/settling. The spectrophotometer was calibrated with test tube five again, and measurements for test tubes one through four were re-taken for the second reading. Absorbency readings were recorded in a table, and color change before and after the ten minutes was noted. What is one possible source of error (besides human error) that occurred in this experiment? Explain in detail. How does this error affect the observed and recorded results (absorbance)?
Electron Transport Chain
The electron transport chain, also known as the electron transport system, is a group of proteins that transfer electrons through a membrane within mitochondria to create a gradient of protons that drives adenosine triphosphate (ATP)synthesis. The cell uses ATP as an energy source for metabolic processes and cellular functions. ETC involves series of reactions that convert redox energy from NADH (nicotinamide adenine dinucleotide (NAD) + hydrogen (H)) and FADH2(flavin adenine dinucleotide (FAD)) oxidation into proton-motive force(PMF), which is then used to synthesize ATP through conformational changes in the ATP synthase complex, a process known as oxidative phosphorylation.
Metabolism
Picture a campfire. It keeps the body warm on a cold night and provides light. To ensure that the fire keeps burning, fuel needs to be added(pieces of wood in this case). When a small piece is added, the fire burns bright for a bit and then dies down unless more wood is added. But, if too many pieces are placed at a time, the fire escalates and burns for a longer time, without actually burning away all the pieces that have been added. Many of them, especially the larger chunks or damp pieces, remain unburnt.
Cellular Respiration
Cellular respiration is the cellular process involved in the generation of adenosine triphosphate (ATP) molecules from the organic nutritional source obtained from the diet. It is a universal process observed in all types of life forms. The glucose (chemical formula C6H12O6) molecules are the preferred raw material for cell respiration as it possesses a simple structure and is highly efficient in nature.
Background:
In this experiment, the lab instructor created a catecholase enzyme solution using white potatoes. The potato was the source of enzymes and cofactors in the experiment, as potatoes have sufficient amounts of catecholase and, therefore, cofactors for catecholase.
A chilled potato had the peel removed by the instructor and then was chopped into pieces. The potato is peeled so that the brown skin does not interfere with the brown color of the benzoquinone. If this were to occur, the absorbance would seem higher due to the brown potato skin in the solution. The potato was chopped so that the blender did not need to work as hard to break open the cells. The instructor then placed the chopped, peeled potato into a chilled blender. The blender is chilled as heat will speed up the
Five test tubes were obtained. 1 mL of the enzyme was added to each test tube first. Next, 2 mL of EDTA was added to the EDTA test tube. Similarly, 2 mL of PTU was added to the PTU test tube, and 2 mL of citric acid was added to the citric acid test tube. Finally, 2 mL of dH2O was added to the distilled water test tube, and 4 mL of dH2O was added to the blank test tube. 2 mL of catechol was added last because the reaction will start occurring as soon as it is added. Initial measurements of the test tubes were recorded, and each tube was placed back into the test tube rack to sit for ten minutes. This procedure was repeated after ten minutes. During this ten-minute period, the tubes were all inverted every two minutes to keep contents within the solution evenly mixed and prevent starch buildup/settling. The spectrophotometer was calibrated with test tube five again, and measurements for test tubes one through four were re-taken for the second reading. Absorbency readings were recorded in a table, and color change before and after the ten minutes was noted.
What is one possible source of error (besides human error) that occurred in this experiment? Explain in detail. How does this error affect the observed and recorded results (absorbance)?
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