KNES 191B Lecture Notes - Lecture 13: Xyy Syndrome, Meiosis, Zona Pellucida
Document Summary
Fertilization, gonads: the organs that produce sex cells. Gametes: sex cells such as sperm and eggs. Chromosomes: packaged dna and protein that contains genes for specific structures and functions. There are 23 pairs (46 chromosomes) for each pair 1 from mom 1 from dad. 23rd pair is sex chromosomes (determines sex of baby: fusion of haploid gametes. Sperm pathway: corona radiata, zona pellucida, plasma membrane of secondary oocyte, and cytoplasm of secondary oocyte: blocks to polyspermy. 1)fast block-almost immediate when sperm makes contact with egg. Zona pellucida- hardens which is permanent: sperm and egg contributions differ. This is why the mother provides mitochondrial dna. Pre-embryo (until gastrulation complete: zygote, undifferentiated, totipotent "stem cell" that can form an organism. Multipotent-can be specialized from pluripotent stem cells stem cells with a specific function: chromosomal abnormalities. Spontaneous abortion (miscarriage) - not exactly 23 pairs which will mean that a blastocyst will not develop. Most do not make it past the infant stage.
