- Slides: 6
Formation of Gametes
Formation of Gametes 1. Anthera. Pollen sacs have diploid cells (microspore mother cells) b. Microspore mother cell---->meiosis---> 4 haploid microspores How is this meiosis similar in human males? Males produce 4 viable sperm cells c. Each microspore undergoes mitosis to produce 2 nuclei in each cell 1. Tube nucleus 2. Generative nucleus What is the ploidy of the tube and generative nuclei? Haploid (N) d. Pollen grain is formed when the outer wall hardens
Formation of Gametes (cont…) 2. Ovulesa. Megaspore mother cell (2 N)----->meiosis---> 4 haploid megaspores b. 3 of the 4 megaspores die c. 1 remaining megaspore undergoes mitosis 3 x---> 8 nuclei (form the embryo sac) Since the megaspore is undergoing mitosis, what is the ploidy of the 8 new nuclei? Haploid d. Polar nuclei- 2 nuclei in the center of the cell e. Egg nucleus- migrates to one end of the cell, will eventually fuse with the sperm cell Through what process will the egg cell fuse with the sperm cell? Fertilization
Summary What is a gamete? A sex cell Compare meiosis in human males and plants. In both 4 viable sperm cells are produced Through what process will the egg cell fuse with the sperm cell? Fertilization In a plant with an imperfect flower, that is a staminate flower, could fruit form? Why, why not? No, because the fruit develops from the ovary, which is part of the pistil. In a staminate flower the is no pistil, therefore no ovary.