O-LevelBiologyPlant Nutrition5090/22 · Oct/Nov 2016 · Q212 Marks
Fig. 2.1 shows part of the flowering head of a small tree that grows in tropical rainforests. [Figure 2.1]
- (a)Identify the structures C, D, E and F shown on Fig. 2.1. C D E F[4]
- (b)(i)Structure D contains stomata similar to those found in the leaves. H, J, K and L represent gases that pass into and out of the leaves and flowers during daylight hours. Identify the gases H and J. H J[2]
- (b)(ii)The flowers are very pale pink in colour. Suggest the identity of gases K and L. Give an explanation for your answer. K L explanation[4]
- (c)Extracts from the tree have many uses in medicine. Some of the extracts are alkaline and have anti-bacterial properties. Some stomach problems are caused by excess acid production. Suggest why these tree extracts are sometimes used to treat such stomach problems.[2]
This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2016). The mark or mark type is shown in brackets.
- [4] C-style/pistil/carpel/gynaecium ;
- D-petal/corolla ;
- E-anther/stamen/androecium ;
- F-fruit/pericarp ;
- [2] H-CO2/carbon dioxide;
- J-O2/oxygen/water vapour ;
- [2] K-O2/oxygen ;
- L-CO2/carbon dioxide/water vapour ;
- no chlorophyll/no chloroplasts;
- no photosynthesis ;
- respiration;
- A transpiration if water vapour given for L;
- [2] neutralises (stomach acid)/raises pH AW ;
- may kill/destroy (harmful) bacteria;
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