The Effect Of Varying Concentrations Succinate On The Rate Of Cellular Respiration of Lima beans (Phaseolus Lunatus) PDF

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This is just an example of the layout and structure of the practical writeup assignment for cellular respiration....

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The Effect Of Varying Concentrations Succinate On The Rate Of Cellular Respiration of Lima beans (Phaseolus Lunatus) Introduction Cellular respiration is simply the process in which Glucose, which is one of the most vital source of carbohydrates present in the diets of all mammals, in the form of starch, which is a storage polysaccharide (Urry et al.), is degraded or broken down and is an exergonic process, releasing energy (Urry et al.). It is also involved in the production of ATP (Adenosine Triphosphate), which contains three phosphate groups. It is specifically known as a sequential process of three metabolic stages which are Glycolysis, the Krebs cycle and the electron transport chain (Flinders University 2021), which together contribute to the chemical breakdown of glucose and the consequential production of ATP. Glycolysis occurs in the cytoplasm, same with the Krebs cycle, and the electron transport chain which occurs in the mitochondria (Flinders University 2021). A particular step involved in the Krebs cycle ( or known as the Citric Acid Cycle) is the conversion of succinate to fumarate in a redox reaction, which is aided or accelerated by the catalysis of enzymes, and the resultant transfer of an electron from one compound to another (Flinders University 2021). In intact cells, succinate loses hydrogen ions to FAD, and as a result of this process, fumarate is formed (Flinders University 2021). In this experiment, according to the aim of the research question that was constructed as a group, specifically the environmental conditions that have an effect of the rate of cellular respiration in lima beans, the varying concentrations of succinate was chosen to investigate its effect in the rate at which cellular respiration occurs in lima beans, and the specific measure used to identify this effect taking place was the rate at which the enzyme catalyzed conversion of succinate to fumarate (Flinders University 2021) in the cytoplasm. Based on this background knowledge and understanding, a subsequent hypothesis was formed. The hypothesis was how the increasing concentrations of succinate would coincide with a resultant increase or greater rate of cellular respiration. In addition, a substance called DCPIP ( di-chorophenol-indophenol) was used to visualize the rate of cellular respiration and this phenomena is further observed through the interception of the electrons and the hydrogen ions released from the succinate and as a result a transposition from its originally oxidised state to a reduced state (Flinders University 2021). Its oxidised state is characterized by a bright blue colour while its reduced state is characterized as a colourless solution (Flinders University 2021). The colour change is used to gauge the rate of cellular respiration dependent on the varying concentrations of succinate (Flinders University 2021) . This colour change is

quantified by using a spectrophotometer (Flinders University 2021).

Method The practical experiment is constituted into two separate parts, in which the first part of the experiment is more like a sample where we observe the effect of varying succinate concentrations on the rate of cellular respiration in the lima beans. The materials used in this part are a spectrophotometer, phosphate buffer, DCPIP of course, succinate and Mitochondrial suspension (Flinders University 2021). The spectrophotometer will be set at 600 nm which is its transmittance for each sample and prior to this the spectrometer will be blanked and set to zero(Flinders University 2021) . Two of them didn’t have succinate except one, which was 0.2 mL. Parafilm was used to cover the open side of the cuvette and invert and mix the contents of mitochondrial suspension, etc. The timer was started to measure the transmittance and at 5-minute intervals for a 30-minute total duration (Flinders University 2021). Afterwards, the second week of the experiment, a research question with controlled variables, hypothesis, treatments, etc were decided from the observations. The succinate concentration concentrations varied this time with low concentration (0.05 mL), moderate ( 0.1mL) and high (0.3mL) and the control was no succinate, but all the other materials from the previous part were included. The spectrophotometer was to measure transmittance at 600 nm and at 5-minute intervals, totalling up to 50 minutes. Data from 5 groups were collected and the mean absorbance at each time was calculated and put as tables.

Results

Table 1: The Average transmittance of the mitochondrial suspension in different concentrations of succinate at every 5-minute interval (total 50 minutes) Sample

Time (Minutes) 0

5

10

15

20

25

30

35

40

45

50

Control(no succinate)

18

27

29

30

30

29

30

29

28

28

30

Low succinate (0.05 mL)

18

32

43

55

60

67

70

72

73

74

75

Moderate succinate (0.1 mL) 20

35

46

55

60

64

69

77

79

79

82

18

37

51

60

65

72

74

77

79

80

81

High succinate (0.3 mL)

The results show that the transmittance across all 3 samples including the control don't actually follow a consistent or stable trend of the increasing concentration of succinate with increase in the transmittance, as it can be observed that there are some hectic fluctuations and sudden increases and decreases throughout the samples at each 5-minute interval and so it didn’t increase in steady increments, but the low succinate and moderate succinate showed some similarity, especially in the early stages. It shows that the sample with the moderate succinate (0.1 mL) had the highest cellular respiration rate with an average transmittance of 1.78% and it was rather interesting and shocking to find that sample 3 containing the highest concentration of succinate had an average transmittance of .89%, even though it had the highest concentration.

Discussion Through this practical experiment and the consequent findings, it has been revealed that the proposed hypothesis was wrong. It shows that the sample with the moderate succinate (0.1 mL) had the highest cellular respiration rate with an average transmittance of 1.78% and it was rather interesting and shocking to find that sample 3 containing the highest concentration of succinate had an average transmittance of .89%, even though it had the highest concentration. So the rate of cellular respiration does not increase or become greater due to increased concentrations of

succinate. Conclusion In conclusion, my hypothesis had been proven wrong. The END.

References: Flinders University (2021). Biology Molecular Basis of Life: General Information and Laboratory Manual. College of Science and Engineering.

Urry, L. A., Meyers, N. M., Cain, M. L., Wasserman, S. A., Minorsky, P. V., & Reece, J. B. (2018).

Campbell

biology

https://www.pearson.con.au

(11th

ed.,

Vol.

1).

Pearson

Australia

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