On Fig. 4.1, indicate whether each labelled cell is haploid or diploid. Write $n$ for a haploid cell and $2n$ for a diploid cell.
Spermatogenesis includes meiosis, mitosis, growth and maturation. State which of these processes is used in each of the following stages of spermatogenesis: spermatogonium to primary spermatocyte; spermatid to spermatozoan (sperm).
Suggest why cultivating this genetically modified wheat might be considered acceptable, but growing genetically modified insect-resistant maize or cotton might be objected to.
State one role played by a Sertoli cell.
Outline the treatment needed to obtain mature oocytes as part of an IVF procedure.
With reference to Table 4.1, describe the effect of adding reproductive hormones on spermatid development after 48 hours.
Suggest a reason for the apparent decrease in the percentage of elongated cells between 24 hours and 48 hours in some of the samples.
Suggest why the culture medium was kept at a temperature of $30^\circ\text{C}$ rather than core body temperature ($37^\circ\text{C}$).
Suggest a reason for the apparent decrease in the percentage of elongated cells from 24 hours to 48 hours in some samples.