Biology 9700 · AS & A Level · Testing for biological molecules

Testing for biological molecules — practice question

Solution X was examined for non-reducing sugars. It contained no reducing sugars. The steps below may be used when testing for the presence of biological molecules. 1. Benedict’s solution is added to the test-tube. 2. Dilute hydrochloric acid is added to the test-tube. 3. Sodium hydrogencarbonate is added to the test-tube. 4. The test-tube is heated in a water-bath. Which sequence of steps is correct for identifying non-reducing sugars in solution X?

  • A$1 \rightarrow 4$
  • B$2 \rightarrow 3 \rightarrow 1 \rightarrow 4$
  • C$2 \rightarrow 4 \rightarrow 3 \rightarrow 1 \rightarrow 4$
  • D$3 \rightarrow 2 \rightarrow 4 \rightarrow 1$

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