Biology 5090 · O Level · Biological molecules

Biological molecules — practice question

A student performed two tests on a liquid sample. After Benedict’s solution was added to part of the liquid and the mixture was heated, it became red. When biuret reagent was then added to the remaining liquid, it changed to mauve (purple). Which conclusion is correct?

  • AThe liquid contained solutions of lipids and glucose.
  • BThe liquid contained solutions of lipids and protein.
  • CThe liquid contained solutions of starch and glucose.
  • DThe liquid contained solutions of glucose and protein.

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