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To be uploaded to CIE. |IGCSE Programme
Biology 0610
Quiz | | |
|Name: ________________________ |Class: ____ |Date: __ / __ / _____ | First Semester 2010 |
|Topic: Enzymes & Food Tests |Mark: out of [13] |Duration: (15 min) |
|Answer all questions. |
Question
|The enzyme amylase speeds up the break down of starch into reducing sugar. |For Examiner's |
|Amylase is present in saliva. |Use |
|Equal volumes of starch and amylase solutions were mixed thoroughly in a container. A sample was removed immediately and tested for presence of | |
|starch, protein and reducing sugar. The remaining mixture was placed in a water- bath at 40 oC and left for one hour. During this time, the | |
|contents were stirred with a clean glass rod at regular intervals. After one hour, a second sample was removed and tested in the same way. | |
|(a) Describe how you would carry out a simple test for starch and reducing sugar. In each case, state the colour changes that would occur if the | |
|results were positive. | |
|Test for starch | |
|………………………………………………………………………………………………………………. | |
|………………………………………………………………………………………………………………. | |
|…………………………………………………………………………………………………………… [2] | |
|Test for reducing sugar | |
|……………………………………………………………………………………………………………… | |
|……………………………………………………………………………………………………………... | |
|……………………………………………………………………………………………………………… | |
|…………………………………………………………………………………………………………… [3] | |
|(b) (i) Record the results of the tests for the sample taken immediately after mixing the starch and amylase solutions and for the second sample | |
|taken after one hour later. [3] | |
|Test | |
|Sample tested immediately | |
|Sample tested after one hour | |
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|Starch | |
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|Protein | |
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| |For Examiner's |
| |Use |
|Reducing Sugar | |
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|(ii) Suggest one reason why the water- bath used in this investigation was set at 40 oC. | |
|………………………………………………………………………………………………………………. [1] | |
|(iii) Suggest one reason why the mixture was stirred at regular intervals. | |
|…………………………………………………………………………….………………………………. [1] | |
|(c) In another investigation, the amylase solution was boiled and cooled and then mixed with the starch solution. A sample was removed | |
|immediately and tested, as before. The remaining mixture was kept at 40 oC and sampled again after one hour. | |
|……………………………………………………………………………………………………………… | |
|……………………………………………………………………………………………………………… | |
|……………………………………………………………………………………………………………… | |
|……………………………………………………………………………………………………………… | |
|……………………………………………………………………………………………………………… | |
|……………………………………………………………………………………………………………… | |
|……………………………………………………………………………………………………………. [3] | |
|[Total: 13] | |
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