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The effect of Temperature on Enzyme Action (Rennin)

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The effect of Temperature on Enzyme Action (Rennin) Aim To investigate the effect of temperature on activity of Rennin Introduction Rennin is an enzyme secreted by walls of the stomach. It acts on a protein in milk causing it to pump into a semi-solid curd. The enzyme is readily available in the form of rennin solution. Enzymes are proteins that catalyze (i.e. accelerate) chemical reactions. In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, the products. Almost all processes in a biological cell need enzymes in order to occur at significant rates. Since enzymes are extremely selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which metabolic pathways occur in that cell. Activity is also affected by temperature, chemical environment (e.g. pH), and the concentration of substrate. Some enzymes are used commercially, for example, in the synthesis of antibiotics. ...read more.


Also care has to be taken for the Bunsen burner because it may cause burn to the skin and also were protective gloves from hazardous chemicals. Variables Independent: - Temperature Dependent:- Is the rate of reaction(time taken for the milk to curdle). Control Variable:- Same amount of Rennin, same amount of milk, same concentration of Rennin, same type of milk and same amount of time the test tubes were left in water bath(5 minutes). Results Time taken for milk to curdle in the presence of Rennin Temperature Experiment 1 Experiment 2 Average 0�C Greater than 60min Greater than 60min (did not curdle) Greater than 60min 20�C Started to clot at 50 mins 35 mins 55 mins 40�C 2 mins 3.5 mins 2.75 mins 60�C Denatured Denatured 80�C Denatured Denatured Time taken for milk to curdle without the presence of Rennin Temperature Experiment 1 Experiment 2 Average 0�C Did not curdle Did not curdle 20�C Did not curdle Did not curdle 40�C Did not curdle Did not curdle 60�C Did not curdle Did not curdle 80�C Did not curdle Did not curdle Discussion questions 1. ...read more.


As temperature increases, so does the enzyme activity, up to a certain point. This is because as the temperature increases, the kinetic energy of the molecules also increases in the reaction, including the enzyme and this increase the speed of reaction decrease. However, after a certain maximum temperature, the enzyme's structure becomes irreversibly changed. After this, the enzyme is said to be denatured and enzyme activity drops rapidly. This is because the changed shape of the enzyme does not allow it to become involved in further reactions. The maximum point before denaturation is called the optimum temperature. This is when enzyme activity is highest. 9. The procedure used is a reliable way of investigating the effect of temperature on enzyme activity. However to get more reliable results, the experiment should be taken at shorter temperature intervals (e.g. 5-10�C) Conclusion Enzymes work best at optimum temperature. In the experiment, the optimum temperature was 40�C. This is because Rennin is produced by the walls of the stomach where the temperature is about 37�C. As temperature increase beyond the optimum, the enzyme activity decreases till it finally stops because enzyme is denatured. As temperature is decreased lower then the optimum, the rate of enzyme activity slows. ...read more.

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