BIOLOGY 172 Lecture Notes - Lecture 34: Pollen Tube, Pollen, Hypocotyl
Document Summary
Similarities: cell proliferation, cell signaling, differentiation, apoptosis. Plant cells do not move during development (cell wall doesn"t allow it) Some plant cells are able to de-differentiate (return back to stem cell) Gametes are haploid: eggs (oocytes) and sperm. Formed in the reproductive organs of adult organisms. Plant gametes cells are created via mitosis (not directly via meiosis) Sperm - 2 sperm nuclei and one pollen tube nucleus. Egg - 3 of 4 haploid cells die, 1 surviving haploid undergoes mitosis 3 times, 8 nuclei formed, 3 top / 3 bottom / 3 middle. Two nuclei in the middle are the central cell. Pollen grain lands on the top of the carpal, pollen tube nucleus start transcribing to create a tube to help 2 sperm nuclei get to the ovule. First sperm creates diploid zygote diploid embryo. Second sperm fuses with the central cell to create a triploid cell triploid endosperm (nourishes plant embryo.
