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Biology Sec 2 Cpt 3- Test for Carbohydrates

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shazzuti's version from 2016-05-06 13:48

Section

Question Answer
Name the tests conducted for the presence of carbohydrates. Iodine test, Benedict's test.
What is the purpose of the Iodine test? To test for starch.
Procedure of the Iodine test? Add a few drops of iodine solution to the sample observe the colour change, if any.
Iodine test: what can you deduce if the sample remains brown? There is an absence of starch in the sample.
Iodine test: what can you deduce if the sample turns into that of a blue-black colouration? There is a presence of starch in the sample.
What is the purpose of the Benedict's test? To test for reducing sugar.
Procedure of Benedict's test? 1. Add 2 cm3 of Benedict’s Solution to an equal volume of a sample in a test tube. 2. Shake to mix thoroughly. 3. Put the test tube in a boiling water bath for 3 to 5 minutes. Observe colour change if any.
Benedict's test: What can you deduce if the solution remains blue? There is an absence of reducing sugar in the sample.
Benedict's test: What can you deduce if green is precipitate formed ?There is a small amount of reducing sugar is present in the sample.
Benedict's test: What can you deduce if yellow/ orange precipitate is formed? There is a moderate amount of reducing sugar present in the sample.
Benedict's test: What can you deduce if brick red/ orange precipitate is formed?There is a large amount of reducing sugar is present in the sample.
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