Yeast Respiration Essay

In this exercise, two experimentations were performed to compare the fermentation rates of yeast under various conditions and measure the cellular respiration in mitochondria that have been isolated from lima beans. For part one, yeast was grown in various carbohydrate solutions as a food source at various temperatures. A yeast suspension was transferred into a fermentation tube and measurements of 〖CO〗_2 produced were recorded. This

Cellular respiration is the method of breaking down organic molecules to release their stored energy. Plants and animals use cellular respiration to use energy. Aerobic respiration is the release of energy from glucose or another organic substrate in the presence of oxygen while anaerobic does not require oxygen. Cellular respiration takes place in the mitochondrion. The three phases of cellular respiration are glycolysis (fermentation), krebs cycle, and the electron transport chain. Carbon dioxide and water are products of the series of reactions involved in cellular respiration. Fermentation is one catabolic process that is a degradation of sugars that occurs without the use of oxygen (Campbell and Reece, 2008). These pathways help generate energy to fuel thousands of chemical tasks in a cell. Fermentation by yeast is used to make beer, wine and bake bread. This process is summarized by:

C6H12O6 → 2C2H5OH + 2CO2 + energy (including 2 ATP)

Glucose is the fuel cells use for respiration, carbon dioxide. Glycolysis occurs in the cytosol and creates two 3-carbon molecules of pyruvate and two molecules of ATP by breaking down glucose. During the aerobic process, pyruvate will lose one of its three carbons as a molecule of 〖CO〗_2, leaving behind a two-carbon acetyl group. Oxygen is re...

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...nts of the buffer, DPIP, mitochondrial suspension and succinate utilized for each tube.

Table 2. Measurements of Each Test Tube. Measurements of solution for each cuvette. ples one through three and a second blank for sample four. A spectrophotometer was set up with a transmittance of 600nm wavelength light for this experiment. Immediately after the cuvettes were properly prepared, they were covered with parafilm and shook vigorously for two seconds to mix the components. The cuvettes were then placed into spectrophotometer and their percent transmittances were recorded. A blank was placed before measuring each cuvette. Table 3 provides the transmittance readings of each samples reduced DPIP.

Table 3- % Transmittance Readings of Reduced DPIP. Percentages from the spectrophotometer are shown over a period of thirty minutes with five minute interval readings.

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