The objective of this experiment is to determine the effect of temperature to the activity of enzyme.

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Biology TAS Experimental Report 1

Aim:

The objective of this experiment is to determine the effect of temperature to the activity of enzyme.

Introduction:

        Enzyme is indeed a globular protein, which is constructed in a 3-dimentional shape held by various bonds such as hydrogen bond. The active size of enzyme is a small part formed by several amino acids which are stabilized by the chemical bonds. Each enzyme has a unique 3-dimentional shape of active size for different metabolism. It is responsible to hold a substrate and form an enzyme-substrate complex, which would then give out the product for living cells. With the increase of temperature, the activity of enzyme also increases because the movement of enzyme is greater and more easily to collide with the substrate to form product. Thus the rate of metabolism would increase.

However, if the shape of the active size is altered, the original function of the enzyme will lose, which is also known as denaturation. There are several ways for enzymes to be denatured, one of them is temperature. Since the bonds for holding the 3-dimentional shape are weak, they could easily be broken down by heat.

        In this experiment, we use amylase from the green beans to convert starch into maltose. The experiment is divided into two parts: the first part is the initial measurement of the enzyme activity, which aims to ensure the normal activity of the amylase; the second part is to mix the starch solution, acetate buffer and the amylase extract together in water baths with different temperature to investigate the effect of temperature on enzyme activities. Moreover, a control set-up should be readied by preparing the mixture of acetate buffer and starch solution without amylase.

Requirements:

Materials:

  • Green beans (20g)
  • Peptone solution (10cm3)
  • Starch solution (15cm3)
  • Acetate buffer (10cm3)

Apparatus:

  • 1 electronic balance
  • 1 Centrifuge
  • 2 strong perspex tubes (used in the centrifuge)
  • 1 Measuring cylinder (10cm3)
  • 1 Glass rod
  • 1 Stop watch
  • 2 droppers
  • 1 spot tile
  • 2 boiling tubes
  • 3 test tubes
  • 1 mortar and pestle
  • 2 beaker
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Procedures:

(Since the time was not enough to do the whole experiment for each group, only one temperature of the mixture was done by different groups.)

  1. 20g of green beans was measured by using the electronic balance.
  2. The beans was put in a mortar and grinded by a pestle to obtain a mixture of beans’ residue and amylase extract.
  3. The mixture was evenly poured into two Perspex tubes.
  4. The perspex tubes were put in the centrifuge for centrifugation; amylase extract was obtained from the upper layer of the product and placed in a test tube.
  5. Meanwhile, a ...

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