
Chemical composition of protein
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Proteins such as enzymes carry out
work in a cell. Protein can also provide structures such as gates,
channels, support rods that give the cell its shape. So what are
proteins, such as enzymes, made of?
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Time for some heat! Gently heat a
small quantity of gelatine crystals (protein) in a test tube, while
holding a piece of moist red litmus paper at its mouth.
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Consider these questions:
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Does water condense on the
sides of the test tube?
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Does the gelatine decompose
leaving a black residue?
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Does litmus paper turn blue?
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What gas produces this change
in litmus?
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What elements do these results
suggest are present in gelatine?
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When heated strongly, gelatine
gives off an odour. What does the odour remind you of?
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You can repeat this experiment with hair or
other protein such as egg.
Answers: