A-LevelBiologyTransport in plantsMay/June 2017Paper 1 Q241 Mark
An aphid, such as a greenfly, uses a tubular mouthpart called a stylet to feed on nutrients in the plant. It inserts the stylet through the surface of a stem or leaf. When a stylet is cut near the aphid's head, leaving the stylet in the plant, a liquid with a low water potential continues to flow out of the plant. Which statement explains this?
AThe stylet is in a phloem sieve tube element in which there is a high concentration of solutes.
BThe stylet is in a phloem sieve tube element in which there is a low concentration of solutes.
CThe stylet is in a xylem vessel element in which there is a high concentration of solutes.
DThe stylet is in a xylem vessel element in which there is a low concentration of solutes.
✓ Correct Answer
The correct answer is A. This question tests the candidate's understanding of transport in plants within the Biologysyllabus. The examiner's mark scheme requires...
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
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