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

Testing for biological molecules — practice question

Four extracts were prepared from different plant materials and then tested using Benedict’s solution. Each extract was boiled with Benedict’s solution for $240$ seconds, after which the final colour was noted: extract 1: red; extract 2: yellow; extract 3: blue; extract 4: green. Which sequence of plant extracts shows an increasing amount of reducing sugar?

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

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