NURSING EXAM QUESTIONS
BIOCHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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it is in a chelate form with rochelle’s salt
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it can interact with free aldehyde groups only
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it can not act with other redicing groups
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all of these
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Detailed explanation-1: -The copper sulfate solution is a blue color and the sodium hydroxide solution is a yellow color. When a reducing sugar is present in a sample, it will react with the copper sulfate solution to produce a red color. The presence of a red color in the test solution indicates the presence of a reducing sugar.
Detailed explanation-2: -Reactions Of Fehling’s Test When the redox reaction is completed, the copper II ions are reduced to Copper I oxide, which forms a red precipitate and is insoluble in water. A positive test result is indicated by the presence of this red precipitate.
Detailed explanation-3: -Glucose reduces Fehling’s solution to reddish brown cuprous oxide.
Detailed explanation-4: -The reducing sugar, when treated with Fehling’s solution, forms a precipitate. This is because reducing sugar has a free aldehyde or ketone group. The formula of glucose is CH2OH(CHOH)4CHO. So, when the glucose reacts with Fehling’s solution it forms red ppt and gluconic acid.