# Life Sciences Paper 1, November 2024, question 3.5.4

> After 72 hours in darkness, the shoots of the seedlings in set Q all curved... Marked mark by mark. Q3.5.4, Life Sciences Paper 1 November 2024, 4 marks.

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Last updated: 2026-11-12

Subject: Life Sciences. Source: Based on Nov 2024 · Paper 1 · Q3.5.4. Marks: 4. Not yet checked by a teacher.

## Question 3.5.4 (4 marks)

A learner investigated how auxins affect the growth of shoots. Twelve seedlings of the same species were split into three sets (P, Q and R) of four seedlings each. All seedlings were kept in darkness for 72 hours.
- Set P: the shoot tips were left on and not treated.
- Set Q: the shoot tips were cut off. A small block of agar jelly containing auxins was placed on the cut surface, but only on the right-hand side of the stump (agar lets substances diffuse through it).
- Set R: the shoot tips were cut off and a block of agar jelly without auxins was placed centrally on the cut surface.
The diagram below shows how the shoot tips of the three sets were treated.

After 72 hours in darkness, the shoots of the seedlings in set Q all curved towards the left-hand side. Explain these results.

Figure: Three seedlings standing in a dark cupboard at the start of the experiment. The first (P) still has its shoot tip. The second (Q) has had the tip cut off and has a small block of agar jelly containing auxins on the cut end, placed on the right-hand side only. The third (R) has had the tip cut off and has a block of plain agar jelly with no auxins on the cut end.

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[Answer this question](https://sharpkop.co.za/life-sciences/2024-nov-p1/q3-5-4/) and see it marked mark by mark, with the reason for every lost mark.

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