Sucrose is a disaccharide - VCE - SSCE Chemistry - Question 5 - 2005 - Paper 1
Question 5
Sucrose is a disaccharide. Bees use an invertase enzyme to convert sucrose to an equimolar mixture of glucose and fructose. The structural formula of sucrose is give... show full transcript
Worked Solution & Example Answer:Sucrose is a disaccharide - VCE - SSCE Chemistry - Question 5 - 2005 - Paper 1
Step 1
i. Give the name of the functional group circled in the structural formula of sucrose.
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Answer
The functional group circled in the structural formula of sucrose is the hydroxyl group (–OH).
Step 2
ii. To which of the major food groups does sucrose belong?
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Answer
Sucrose belongs to the carbohydrate food group, which is primarily composed of sugars and starches.
Step 3
iii. Given that glucose has a six-membered ring structure, draw the structural formula of glucose.
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Answer
The structural formula of glucose can be represented as:
H OH
| |
H – C – C
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OH H – C – OH
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H H
This diagram represents the cyclic structure of glucose, where the carbon atoms form a six-membered ring.
Step 4
What simple molecule is the other reactant in the conversion of sucrose to glucose and fructose?
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The other simple molecule in the conversion of sucrose to glucose and fructose is water (H₂O).
Step 5
Explain why the percentage yield is higher at 35°C than at 5°C.
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At 35°C, the enzyme exhibits optimal activity for the breakdown of sucrose into glucose and fructose, resulting in a significantly higher percentage yield of glucose than at 5°C, where the enzyme activity is greatly reduced due to lower temperatures.
Step 6
Explain why the percentage yield is higher at 35°C than at 95°C.
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At 95°C, the high temperature likely denatures the enzyme, leading to a dramatic drop in its activity. Therefore, the percentage yield of glucose is much lower at this temperature compared to 35°C, where the enzyme remains active.
