How enzyme concentration affects the amount of apple juice production.

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How enzyme concentration affects the amount of apple juice production.

For this investigation I am going to investigate the effect of the concentration of an enzyme, in this case Pectinase, on the time taken for the enzyme to breakdown the substrate, which in this case is an apple. The reason Pectinase is used is because it breaks down the pectic substances found within, and between, the cell walls. The pectin's are found between the cellulose and hemi cellulose of the cell wall and also in between the cells. It acts as the glue that holds them together. The diagram shows how.

I am going to find out how the enzyme affects the speed in which this is done. I am going to do this by planning an experiment, carrying out the experiment, recording any relevant results and plotting graphs from which I will be able, hopefully to gain a strong conclusion. I will finally evaluate the whole investigation.

Planning

Before the experiments starts we were given a test tube containing a Pectinase. From this we can use as much as we want in a certain test tube. I cannot start he experiment until I know which factors I am going to change and which I am going to keep constant. Because the thing I am trying to test in the effect of the concentration of the enzyme, the only thing that I should be changing in each experiment is the concentration of the enzyme and nothing else. This will make all of the tests identical (apart from the enzymes concentration) which means the experiment should be accurate and fair. Because of this any differences in the results of my experiment I will be able to put down to the concentration of the enzyme. If I was to use two variables, and there were a difference in the results, e.g. I changed the temperature as well as the concentration of the enzyme and the reaction sped up, I would not know which of the factors had done this and therefore could not reach a valid conclusion. I will measure the amount of solution from the apple by using a filter paper and measuring the amount of solution that gets through. Things that have to be kept constant throughout all of the experiments

Temperature:- It is vital that the temperature remains the same in all the experiments as this will have a great impact on the results if not. This is because if the temperature increase the Pectinase molecules will begin to move faster due to the kinetic theory. Because of this Pectinase molecules will bump into and come into contact with the cell walls more often causing the walls to be broken up by the active sites of the Pectinase. This will lead to an increase in rate of reaction. If however the temperature rises too much (above about 60 degrees) the ionic and hydrogen bonds holding the Pectinase together will break causing the active sites on the enzyme to become denatured, this will completely stop the enzymes working and therefore the break down of the cell walls will stop thus causing the rate of reaction to stop. The diagram shows how enzymes break down there specific substrate.
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Concentration of substrate:- If there are more enzymes (Pectinase molecules) than substrate (the cell walls) molecules and then more substrate is added the rate of reaction will increase because there will now be more active sites available for the walls to be broken up in but if there is enough substrate to occupy all the active sites on the enzymes then the rate of reaction will not change and for this reason I will use the same amount and the same concentration of substrate for all of the experiments. This meaning all the concentrations of Pectinase will be ...

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