The diagram shows the human life cycle. The components of the diagram are not drawn to the same scale. The diagram shows: cells L, M and N two types of cell division, K and O. [Figure 6.1]

Mark scheme

Marking points from the official mark scheme (May/June 2021). The mark or mark type is shown in brackets.

1. [1] gamete(s); Ig sex cell
2. [3] 1 M + haploid / 23 chromosomes ;
3. [3] 2 M + only X chromosome ;
4. [3] 3 N + diploid / 46 chromosomes / 23 pairs of chromosomes ;
5. [3] 4 N + either XX or XY chromosomes ;
6. [1] K + meiosis;
7. [1] O + mitosis;
8. [4] (marking points 3–8 must be linked to meiosis or to K if meiosis not named) 3 reduction division;
9. [4] 4 chromosome + number halved / 46 to 23;
10. [4] 5 diploid + to haploid;
11. [4] 6 four daughter AW cells ;
12. [4] 7 genetically different ;
13. [4] 8 takes place in + testes / ovaries / gonads ;
14. [4] (marking points 9–13 must be linked to mitosis or to O if mitosis not named) 9 chromosome + number maintained / 46 to 46 ;
15. [4] 10 diploid + to diploid ;
16. [4] 11 genetically identical / clones ;
17. [4] 12 growth ;
18. [4] 13 two daughter AW cells ;