DP Biology (first assessment 2025)

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Question 22M.2.SL.TZ2.a

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Date May 2022 Marks available [Maximum mark: 4] Reference code 22M.2.SL.TZ2.a
Level SL Paper 2 Time zone TZ2
Command term Describe Question number a Adapted from N/A
a.
[Maximum mark: 4]
22M.2.SL.TZ2.a

Describe how plants transport organic compounds from where they are made to where they are stored.

[4]

Markscheme
  1. (overall) process is translocation / bidirectional / movement from source to sink;
  2. sugars/sucrose/organic compounds produced in leaves;
  3. (loaded by) active transport / passage by apoplast route;
  4. loaded into companion cells / transported in phloem / sieve tubes;
  5. high concentrations of solutes at the source cause uptake of water (by osmosis);
  6. water provides hydrostatic pressure for transport (from source to sink);
  7. unloaded / stored / used at sink;
  8. lowers pressure at sink / creates pressure differential / water re-entry to xylem;
Examiners report

Question 6 was the least popular in section B.

Most candidates provided correct and complete details of the process of translocation.

Syllabus sections