Not sure on the answers to 8,9, and 10 Experiment 2. Cellular Respiration In thi

Question

Not sure on the answers to 8,9, and 10 Experiment 2. Cellular Respiration In this lab exercise, you will investigate aerobic cellular respiration in baker's yeast. At one step in the Krebs cycle, succinate is converted to fumerate in a redox reaction (Fig. 3). We will use this step in the Krebs cycle to study the rate of aerobic cellular respiration under different conditions. We will add a substance called DPIP (di-chlorophenol-indophenol). DPIP is an electron acceptor that intercepts electrons released from succinate. This changes DPIP from an

Explanation / Answer

Aerobic cellular respiration is the process that uses oxygen and yields many more ATP molecules than anaerobic cellular respiration, which does not use oxygen and yields just two ATP molecules. There are broadly three stages in this process of transforming glucose to ATP:

Succinate dehydrogenase (SDH) or respiratory complex Complex II is an enzyme complex which catalyzes the step 6 of the citric acid cycle which is the oxidation of succinate to fumarate and is found in many bacterial cells and in the inner mitochondrial membrane of eukaryotes.

8. The hypothesis of the given experiment is that if an increased amount of succinate was present then the rate of cellular respiration would be higher and greater. Hence, this can be verified by suitable experiments to test the effect of the increased amount of substrate on the rate of cellular respiration.

9. While we predict the results of our experiment based on our hypothesis, the results suggested that cellular respiration has occurred. Immediately when succinate is added to the sample, the Spectrophotometric reading usually reads 0.4. but as time passed, succinate loses the electrons and the hydrogen ions to form fumarate. The DPIP thus takes in these electrons and starts to become oxidized.

10. In the given experiment, the spectrophotometer is the most important tool to derive the hypothesis. We are testing the sample by a spectrophotometer for signs of cellular respiration. DPIP (Dichlorophenolindophenol) used as a redox dye. When oxidized, DPIP is blue with a maximal absorption at 600 nm; whereas when it is reduced, DPIP is colorless. To measure this color change, the spectrophotometer was used. As DPIP becomes oxidized and colorless, less light is absorbed which can show that cellular respiration has occurred or is occurring.

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