A researcher investigated transport in a sunflower plant.
The roots were supplied with water containing a tracer in the nitrate ions. A mature leaf halfway up the stem made sugars containing a different tracer.
Equipment measured each tracer separately. The background count rate was 15 counts per minute. A count rate close to the background indicates that no tracer was detected.
Six hours later, the researcher measured the tracers in tissues P and Q at two positions in the stem.
| Tissue | Nitrate ion tracer below the mature leaf in counts per minute | Nitrate ion tracer above the mature leaf in counts per minute | Sugar tracer below the mature leaf in counts per minute | Sugar tracer above the mature leaf in counts per minute |
|---|---|---|---|---|
| P | 860 | 540 | 16 | 14 |
| Q | 14 | 16 | 470 | 320 |
Which transport tissue is P and which transport tissue is Q?
Use the results to explain your answers.
The transport through tissue Q below the mature leaf is then blocked.
Explain why the growth of the roots may become slower.
74 exam-style questions on AQA GCSE Biology 2.3 Plant tissues, organs and systems, covering 2.3.1 Plant tissues and 2.3.2 Plant organ system. Each one has a worked solution and a mark scheme showing where the marks go.