Describe the process of translocation in a plant, including the tissue involved, the substances transported, and the direction of movement.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Translocation occurs in the phloem.
Sucrose (and sometimes amino acids) are the substances transported.
The movement is from source tissues (e.g. leaves) to sink tissues (e.g. roots, fruits, growing shoots).
Translocation can occur in both directions, up and down the plant.
Sucrose (and sometimes amino acids) are the substances transported.
The movement is from source tissues (e.g. leaves) to sink tissues (e.g. roots, fruits, growing shoots).
Translocation can occur in both directions, up and down the plant.
Examiner tips
- Use the exact terms "phloem", "sucrose", "sources" and "sinks".
- Show the direction (upwards and downwards) to gain full marks.
- Keep the answer brief and to the point.
Common mistakes
- Confusing xylem with phloem.
- Omitting the direction of movement.
- Using vague terms like "carbohydrates" instead of "sucrose".
Mark scheme (4 marks)
- Translocation occurs in the phloem
- Sucrose (and/or amino acids) are the substances transported
- Substances move from sources to sinks
- Translocation can occur in both directions (up and down the plant)
Key terms in this question
Related
- All Cambridge International IGCSE Biology (0610) revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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