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

Testing for biological molecules — practice question

A large number of aphids were used to obtain samples of the contents of the sieve tubes in a tomato plant. Different samples of sieve tube solution were tested. Which result was correct?

  • ABenedict’s test before hydrolysis: blue; Benedict’s test after hydrolysis: blue; iodine solution: blue-black
  • BBenedict’s test before hydrolysis: blue; Benedict’s test after hydrolysis: red; iodine solution: orange
  • CBenedict’s test before hydrolysis: red; Benedict’s test after hydrolysis: blue; iodine solution: blue-black
  • DBenedict’s test before hydrolysis: red; Benedict’s test after hydrolysis: red; iodine solution: orange

Worked solution & mark scheme

This 1-mark question has a full step-by-step worked solution and mark scheme.

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI