O-LevelBiologyEcology & Environment5090/22 · May/June 2014 · Q57 Marks
Cacti are plants that grow in desert conditions. [Figure 5.1] shows a type of cactus. [Figure 5.1] shows leaves reduced to form spines and a green, flattened stem. [Figure 5.2] shows the surface of the stem of the cactus seen using a microscope.
- (a)(i)State two processes that would normally occur in the leaves of a plant.[2]
- (a)(ii)Suggest why it is an advantage for a cactus to have leaves with a small surface area.[2]
- (b)(i)Name the part labelled M on [Figure 5.2][1]
- (b)(ii)Suggest why there are many of these structures on the stems of a cactus.[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 (May/June 2014). The mark or mark type is shown in brackets.
- [2] photosynthesis/synthesis of carbohydrate/synthesis of protein ;
- transpiration/water loss/evaporation ;
- respiration;
- translocation ;
- osmosis/diffusion ;
- gas exchange ;
- [2] lack of (available) water ;
- transpiration/evaporation/water loss + reduced ;
- [1] stoma(ta)/guard cell(s);
- [2] none/fewer on leaves ;
- passage of O2/CO2/water vapour/gas exchange ;
- i.e. not just a CO2/O2/water vapour ref.
- for respiration/photosynthesis/transpiration ;
Write your answer and get it marked
On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.
Sign up free →