What Is the Difference Between Catalase in Potato and Liver in Terms of Optimal Temperature and Ph?

What is the difference between catalase in potato and liver in terms of optimal temperature and pH?

Enzymes are biological catalysts, and are present in living organisms to catalyse metabolic reactions. Their function is to speed up the rate of a reaction by providing an alternative pathway with a lower activation energy barrier. They are not used up in the reaction and can be reused. Their specificity of their active site and function is determined by their tertiary structure, allowing them to bind and act on one substrate only.

Catalase is an intracellular enzyme that found in found in all cells. Catalase catalyses the decomposition of hydrogen peroxide into oxygen and water. This is a catabolic and exergonic reaction. This can be demonstrated by this equation:

H2O2 —> O2 + H2O

Hydrogen is a naturally occurring byproduct of the chemical reactions occurring in living organisms. The toxic substance will be harmful to the body in excessive amounts. The products of catalase can be converted into usable substances.

Liver tissue has more catalase than potato tissue because hydrogen peroxide is a byproduct of cellular respiration, and liver detoxifies our body. Potato cells do not need catalase in large quantities hence it is less abundant.

Depending on the species, enzymes function optimally at a particular pH and temperature.The efficiency of the enzyme is dependent on its conditions. Denaturation is the process of altering a protein’s shape so it is rendered biologically inactive and thus, non-functional. The process is irreversible. There are some factors that can lead to this: temperature and pH.

When exposed to temperatures above the optimum, the breakage of bonds lead to denaturation. When exposed to lower temperatures, rate of reaction is slowed as the enzyme is not flexible enough to undergo conformational change. When exposed to acids beyond the optimum pH, (either above or below the pH), the enzyme can also be denatured.

Aim

To investigate compare the efficiency of potato and liver catalase (measured by oxygen yield) in differing pH and temperature conditions.

Hypothesis

It is hypothesised that liver will produce more oxygen than potato cells under all of the conditions. It is also hypothesised that liver will function more efficiently in a warmer environment, and potatoes, in a cooler environment. Both will perform poorly in acidic and basic conditions.

Variables

IV - changes in temperature, changes in pH and source of catalyst.

DV - amount of oxygen (measured by DO2)

Controlled - same sized cubes of liver and potato pieces, intervals at when time was measured, amount of hydrogen peroxide, time pieces were soaked for, same sized conical flasks.

• Oxygen sensor apparatus + computer

• Kettle

• Cutting board and knife

• Gloves

LILY

Introduction

Methodology

Results

Temperature on Concentration (DO2) of Oxygen Yield

Animals, in general, have a high body temperature to optimise the rate at which metabolic reactions occur. Thus liver performs better in warmer conditions. On the other hand, potatoes are ‘cool weather crops’ , and are usually grown in the cooler months of the year. According to ‘International Year of the Potato’, potato have an optimum yield temperature within the 18 to 20°C range.

Random errors were observed in our second trial with potatoes. The results contradicted the first trial of result - potatoes in the acid reaction had the highest oxygen yield.

Limitations included only conducting tests once. Fresh liver was not available and the species the organism was sourced from is unknown, hence results cannot be generalised to all different kinds of liver.

To improve the experiment, the tight sealing of oxygen sensor in the flask’s neck could have been considered to prevent oxygen gas escaping and hence skewing results. Larger pieces of liver and smaller amounts of hydrogen peroxide could have also been considered to improve precision, as the decomposition reaction was not finished at the 1 minute mark. Different sources of liver should have been used to increase sample size and account for different species. Multiple trials could’ve been carried out to minimise random errors and improve precision. The oxygen sensor should be calibrated.

Conclusion

The hypothesis was partially supported by the evidence.

Overall, the liver is the more effective catalyst overall when exposed to varying temperatures and pH.

Liver catalase performs the best in acidic and warmer conditions, whereas the potato performs the best in warmer and in neither acidic or basic conditions.

References

• 6 x ice cubes Cold

• 30cm ruler

• Solutions - 0.1M HCL, 0.1M NaOH and 3%