Plant ‘thermometer’ triggers springtime growth by measuring night-time heat: reading answers and analysis
Cambridge scientists found that phytochromes, the molecules plants use to sense light by day, act as thermometers at night: the warmer the night, the faster they switch off and let growth resume. This explains early budding in warm winters and the oak-and-ash weather rhyme, and it could help breed crops that cope with rising temperatures.
Questions 27-40 · 14 marks · 3 question blocks
Where the answers sit
TRUE / FALSE / NOT GIVEN (27-32) covers A to E. Section matching (33-37) spans A to H. The sentence completions (38-40) are in G and H.
Questions 27-32
The two FALSEs are about phytochrome behaviour in E: plants grow faster in shade, when phytochromes switch off, and the switch takes under a second by day but happens gradually at night. The NOT GIVENs add other scientists' surprise and water needs, which the passage never mentions.
| Question | Answer | Also accepted |
|---|---|---|
| 27 | NOT GIVEN | — |
| 28 | TRUE | — |
| 29 | TRUE | — |
| 30 | NOT GIVEN | — |
| 31 | FALSE | — |
| 32 | FALSE | — |
Questions 33-37
A names the journal Science. C has farmers and gardeners predicting harvests from buds. D has the benefit of breeding hardier crops, and G explains the oak-and-ash rhyme. The nearby collaborators who can apply the findings are in H.
| Question | Answer | Also accepted |
|---|---|---|
| 33 | H | — |
| 34 | D | — |
| 35 | G | — |
| 36 | C | — |
| 37 | A | — |
Questions 38-40
G gives the daffodil and rhyme answers: daffodils flower early in warm weather, and ash before oak means a wet summer. H names the plant used in the research. The answer key accepts one- and two-word versions of the daffodil and mustard answers.
| Question | Answer | Also accepted |
|---|---|---|
| 38 | warm | warm winter |
| 39 | summer | — |
| 40 | mustard plant | mustard plants / mustard |
The questions most people get wrong
FALSE. Sunlight activates phytochromes and slows growth, so a plant in shade grows faster to escape it.
TRUE. Yields need to double by 2050, and climate change is a major threat to achieving this, so the target could be missed.
H. The 'outstanding collaborators' who work on applied plant biology are the specialists who can use the findings. D gives the benefit, not the people.
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