O-LevelBiologyPlant Nutrition5090/21 · May/June 2021 · Q17 Marks

The diagram shows a root hair cell from a lemon tree and some soil particles. root hair cell. air spaces soil particle

(a)(i)State one feature, visible in the diagram, which shows that a root hair cell is a plant cell.[1]
(a)(ii)Describe how mineral ions pass from the soil into the root hair cell.[4]
(b)The lemon tree has grown in the same soil for many years so the soil now lacks magnesium. Describe and explain the effect on the lemon tree of a lack of magnesium.[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 2021). The mark or mark type is shown in brackets.

[1] cell wall or large/central / sap + vacuole ;
[1] dissolved in water;
[1] through the cell wall ;
[1] carriers in membrane ;
[1] through the cell / partially permeable AW + membrane ;
[1] by active transport / diffusion ;
[1] correct reference to concentration gradient;
[1] using energy (for active transport) ;
[1] from (aerobic) respiration (for active transport);
[1] yellowing / chlorosis / reduced growth / cannot photosynthesise / make glucose / starch / sugar / carbohydrate ;
[1] deficiency of chlorophyll ;

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.