Meiosis and mitosis are key events in the life cycles of organisms. Fig. 3.1 illustrates the life cycles of two different organisms. Organism 1 has a simple life cycle. Organism 2 has a more complex life cycle. It includes a stage A that makes spores and a stage B that makes gametes. In the diagrams, the haploid chromosome number is shown by $n$. The diploid chromosome number is shown by $2n$.
(a(i))[3]
Table 3.1 matches the letters P to T in Fig. 3.1 with the kind of nuclear division. Put a tick (✓) in each row to show the type of nuclear division occurring at each of the letters, P to T.
(a(ii))[1]
State the name of process W that is shown in Fig. 3.1.
(a(iii))[5]
Complete the statements about stem cells and body cells.
Stem cells are [BLANK] cells that divide by [BLANK] to make daughter cells that can become [BLANK] for a particular function.
Most body cells in an organism carry the same genes, but many genes in one specific cell are not [BLANK] because the cell makes only the particular [BLANK] it requires.
(b)[2]
State the events in the life cycle diagram for organism 1 in Fig. 3.1 that would not appear in a life cycle diagram for asexual reproduction.
Worked solution & mark scheme
This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: “P and R indicate meiosis; Q, S and T indicate mitosis” …