development of female plant gametes

Question 1

outline the structure of an ovule

Answer 1

1) each ovary contains 1 or more ovules
2) the ovule consists of two walls called integuments
3) there is a small opening in the integuments where the pollen tube will enter
4) the nucellus contains cells that provide nutrients for the growth of the ovule

Question 2

outline ovule production

Answer 2

1) in the ovule a mother megaspore divides by meiosis to form 4 haploid cells called mega spores
2) 3 of these cells degenerate and one megaspore survives
3) the haploid nucleus undergoes three meiotic divisions producing 8 haploid nuclei
4) the 8 nuclei are divided into three antipodal cells at the top, 2 polar bodies in the centre and 2 synergids either side of an oosphere at the bottom of the now swollen megaspore
5) the two polar bodies in the centre fuse together producing a diploid polar nucleus

Question 3

what should be present in the embryo sac of a mature ovule

Answer 3

1) 3 antipodal (haploid)
2) 2 synergids ( haploid)
3) 1 oosphere (hapolid)
4) 1 polar nucleus (diploid)

Question 4

what is the name of the gap between the integuments called

Answer 4

the micropyle