enzymes worksheet

INTERNATIONAL TURKISH HOPE SCHOOL-CHITTAGONG BRANCHBIOLOGY WORKSHEET – CLASS ……TOPIC: …………………………………….

NAME:……………………………………. DATE: ……………1. In an experiment to study the effect of temperature on the action of an enzyme for coagulating milk. Milk and the

enzyme were first kept in separate test tubes in a water bath at T oC for 15 minutes before they were mixed. The resulting mixture was kept in the same water bath. The time taken for milk to coagulate was noted and the experiment was repeated by using water baths at different temperatures. The time taken for the milk to coagulate at different temperature is shown in the table below.

Temperature of water bath (T o C) Time taken for coagulation ( m inutes)

10 No coagulation occurred.

20 7

30 4

40 2

50 4

60 No coagulation occurred.

(i) What is the purpose of keeping the milk and enzyme in the water bath for 15 minutes before mixing? [01]

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(ii) At which temperature was the enzyme most active? [01]

_______________________________________________________________________________(iii) State and explain whether there would be any change in the results if the mixture originally kept at 10oC was

warmed to 30oC. [03]

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(iv) What control experiment should be carried out to confirm that the coagulation of milk was due to the action of an enzyme? What was the expected result? [03]

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(v) State one factor, other than temperature, that can affect the activity of enzymes. [01]

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NAME:……………………………………. DATE: ……………2. The drawing below shows how a certain biochemical reaction takes place inside the small intestine of a mammal:

(i) Which molecule is an enzyme? (1 mark)

_______________________________________________________________________________(ii) Which are the substrate(s) and product(s) of this reaction? (4 marks)

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_______________________________________________________________________________(ii) What is the name of the part of the enzyme that determines the specificity of the reaction?

(1 mark)

_______________________________________________________________________________(iii) Draw a simple sketch to show the relationship between enzyme activity and

(1) temperature.(2) pH.

(1) (2)

(4 marks)(iv) Give an example of this type of reaction in the small intestine and state the products of the reaction.

(2 marks)_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________


NAME:……………………………………. DATE: ……………3. Tom prepared an experiment to investigate the action of an enzyme. The test tubes were placed in a water bath at

37°C.At the beginning 3 minutes later 30 minutes later

cloudy cloudy clear

(i) Name the enzyme. (1 mark)

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(ii) Explain why the suspension became clear. (1 mark)

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(iii) Suggest with reason one method to speed up the action. (3 marks)

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(iv) Predict and explain the result if the test tube is placed in a water bath at

(1) 80°C. (2 marks)

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_______________________________________________________________________________(2) 0°C. (2 marks)

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10 cm3 of egg white

2 cm3 of enzyme suspension was added and stirred


NAME:……………………………………. DATE: ……………4. The following experiment was carried out to study the properties of a washing powder containing a biologically

active substance X.

(i) Describe the action of substance X on the protein coat. (2 marks)

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(ii) What is the effect of boiling on substance X? (1 mark)

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(iii) Name substance X. Explain why this washing powder can remove egg stain from clothes. (3 marks)

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(iv) It is not advisable to use this washing powder with water at temperatures above 60oC. Explain why. (1 mark)

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(v) It is also suggested not to use this washing powder together with bleaching solution. Explain briefly. (2 marks)

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film with a layer of protein coat

washing powder solution

boiled washing powder solution

protein coat

absent

protein coat

present

A B

After 2 hours

enzymes worksheet

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