Bacterial Energetics and Membranes

M Malone (ml) 0. 15 M KEN (RNA) 0. 75 Total Volume (ml) 20 Discussion During this experiment, several errors prevented the data collection for assays A, B and C, data was collected from an adjacent group. First, the instructions were not properly examined, resulting in the addition of ETC before TAP in several tubes from each assay. This was an enormous error as the reaction was halted before Pi production could begin. Secondly, the intervals at which absorbency values were read were not within the specified 2. Minute time-frame, which would result in a higher amount of Pi present in each tube. Lastly, transferring 0. 250 ml aliquots from the original tube to a micro-centrifuge tube, and back to the clean tubes provided petting errors that decreased the amounts of Pi present in each tube. Several assays were conducted – four Tapes assays and one ETC assay- to observe the assay with Pi and NSA/ acid moldboard reagents, a blue color in the reaction mixture gradually increased in darkness from tubes 1-6, containing 0. -0. 5 ml of Pi, respectively.

In addition, a higher absorbency reading was obtained as the amount of Pi increased per tube. Thus, the color intensity, and absorbency values read at Mann, provide a measure of the amount of Pi present in each tube. The values obtained from this assay were used to produce a standard curve (Fig. 1 . ) from which the amounts of Pi in assays A and B were calculated (Sample Calculations). The calculated amounts of Pi in assays A and B (Fig. 2. ) showed that assay B produced lower amounts of Pi in the absence of MGM+, than assay A, that contained MGM+, 0. 337, and 0. 02, respectively, at the 10 minute interval.

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This suggests that the MGM+/ Ca+ TAP syntheses is dependent upon MGM+ binding to produce optimal levels of P’, or the reverse, TAP. Values collected for the oxygen consumption assay showed that the sample containing NADIA consumed the most 02, as indicated by the largest decrease (9. 8 pimp at T=O, to 0. 2 pimp at T=II), while the sample with KEN consumed the least amount of 02 with the smallest decrease in 02 concentration (remaining steady at 8. 65 pimp). In addition, the sample given Malone also showed a sharp decline in 02 concentration with 9. Pimp at T=O, to 1. 1 pimp at T=II.

This suggests that Malone and NADIA are excellent substrates for the ETC as more oxygen was consumed during a 10 minute span than any other samples, with NADIA 02 consumption slightly higher. This correlates with a higher activity of the ETC as electrons are removed from NADIA and Malone, and subsequently passed down the ETC to pump H+ ions out of the cytoplasm. The sharp depletion of 02 in both treatments suggests that 02 is quickly reduced to H2O during this process. In addition, the treatments containing buffer, membranes, and NADIA + KEN maintained elatedly constant oxygen concentrations throughout the assay.

The treatment containing buffer and membranes should not have any activity as the ETC is not present, or provided with a substrate to oxidize. In the NADIA + KEN sample, a minimal decrease in 02 concentration suggests that it has inhibitory effects on the activity of the ETC, as substrate was provided (NADIA), but was not utilized. Thus, optimal ETC activity can be achieved with NADIA and inhibited with the addition of KEN. While the literature values for the P:O ratio are 2, the data collected here yields a ratio of 1. , resulting in an experimental error value of 30%.

This could be due to experimental error such as incorrect addition of reagents, to petting errors, or possibly miscalculations. Respiration can be classified as aerobic, or anaerobic, and occur by two different mechanisms; oxidative phosphorescently, and substrate-level phosphorescently. The former requires an ETC to produce an ion gradient that is used to turn the Tapes to form TAP. In aerobic respiration, the final electron acceptor is oxygen, while in anaerobic respiration, nitrate, sulfate, or other organic compounds re the final electron acceptors.

While fermentation can occur with, or without the presence of oxygen -occurs more neurotically-, it differs from oxidative phosphorescently in that the ETC is absent. There is no oxidative phosphorescently coupled between the ETC and Tapes. Instead, substrates, such as glucose, are directly oxidized to produce a lower amount of TAP. In conclusion, optimal Tapes activity can be achieved with the addition of MGM+ while optimal ETC activity can be operating capacity is a higher output of TAP production for cellular energy.

from Nandarnold

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