Cell Structure and Function, Enzymes, Research Paper

Enzymes

1. How does temperature affect enzyme function?

Every enzyme demonstrates maximum activity at a particular temperature known as its optimum temperature. Generally, all enzymes are inactivated at temperatures below 10°C and get denatured (lose its three-dimensional protein nature) above its optimum temperature (Seager & Slabaugh 2010).

Experiments conclude that enzyme activity increases by almost ten percent coupled to each degree rise in temperature until it reaches its optimum state and declines beyond it as they start denaturing (Seager & Slabaugh 2010).

2. Do plants and animals have an enzyme that breaks down hydrogen peroxide? How could you test this?

The process of converting toxic hydrogen peroxide into harmless substances occurs at a very slow rate; therefore, both plants and animals have enzymes to catalyze it. Catalase is an enzyme that is present in animal cells; however, plants possess enzyme peroxidase to carry out this decomposition (Seager & Slabaugh 2010).

It can be tested by mixing hydrogen peroxide and a piece of animal liver (containing catalase) or a piece of potato (source of peroxidase) in a test tube. Bubbles of gas will be observed showing the decomposition of hydrogen peroxide (Seager & Slabaugh 2010).

3. How does the boiling water affect the overall reaction?

Boiling water has a temperature that is much higher than the optimum temperature of catalase and peroxidase, therefore; it will denature the enzymes thus causing a decrease in the rate of reaction (Seager & Slabaugh 2010).

4. How can enzyme activity be increased?

Enzyme activity can primarily be increased by adjusting the surrounding temperature and pH to achieve optimal state for an enzyme-catalyzed reaction (Seager & Slabaugh 2010).

5. Design an experiment to determine the optimal temperature for enzyme function, complete with controls.Where would you find the enzymes for this experiment? What substrate would you use?

Place equal volumes of hydrogen peroxide (prepared in lab) in 5 test tubes and pieces of cow liver (equal in mass and dimensions) -- containing catalase in other 5 test tubes. Place ice in one beaker (0°C) and put one test tube of H2O2 and one test tube containing liver in this beaker. After 10-15 minutes, add H2O2 to liver and measure the height of bubble column after 20 seconds. Repeat the experiment at room temperature using new samples of enzyme and substrate. Then prepare a water bath (37-38°C) using beaker and thermometer and follow the same procedure. Furthermore, raise the temperature of water bath to 50-55°C and perform the same steps. Control experiment can be set up by adding water to enzyme instead of substrate at all temperature values. At optimum temperature, the height of bubble column will be highest.

6. Draw a graph using balloon diameter vs. temperature. What is the correlation?

Balloon diameter is directly related to the temperature. As increase in temperature causes expansion of gas molecules, therefore, the volume and thus the diameter of balloon also increases (Seager & Slabaugh 2010).

7. Do you expect more enzyme activity if the substrate concentration is increased or decreased? Draw a graph to illustrate this relationship.

With an increase in substrate concentration, enzyme activity will significantly increase at initial values. However, as the active sites of enzymes get occupied by substrate molecules, the rate of reaction will not remain dependent prominently on the amount of substrate as then substrate molecules have to queue.....