L4: Sex Determinatino Flashcards
What is monoecious?
Both male & female reproductive structures in the same organisms
What is dioecious?
Individuals possessing only male/female reproductive structures
Define intersexIn
Individuals of an intermediate sexual condition (infertile)
What is the female reproductive structures in a plant made up of?
Stigma + pistil
What is the male reproductive structure in the plant?
Stamen
Production of female gametes in the pistil
- Diploid megaspore mother cell undergoes meiosis to produce megaspores (4 haploid nuclei’s)
- 3 of the 4 nuclei degrade, left with a megagametophyte (1 haploid nucleus)
- it undergoes 3 rounds of mitosis to produce an embryo sac of 8 haploid nuclei
What are the different nucleii’s in the embryo sac in the pistil?
3- antipodal nucleii
2- endosperm nucleii
2- synergids
1- oocyte nucleus
Which nucleus contributes DNA to the next plant?
Oocyte nucleus
Describe the events of pollination & double fertilisation
1) Pollen transfer from stamen (male) to stigma (women)
2) Pollen tube grows towards embryo sac
3) 2 sperm nuclei enter embryo sac
What do the sperm nucleus unites with in the embryo sac?
1 sperm nucleus unites with 2 endosperm nucleii
1 sperm nucleus unites with haploid oocyte nucleus
Scientific term for 1 sperm nucleus unites with 2 endosperm nucleii
Triploid endosperm nucleus
Scientific term for 1 sperm nucleus unites with haploid oocyte nucleus
Diploid zygote nucleus
Define homogametic
Only produce 1 type of gametes, carrying a single X chromosome (XX)
Define heterogametic
Produce 2 types of gametes, X & Y chromosome
What is aneuploidies?
Failure of homologous chromosomes to separate properly during meiosis
