MBG 1000 Lecture Notes - Lecture 3: Primitive Streak, Gonadal Ridge, Endoderm

• School: University of Guelph
• Department: Molecular Biology and Genetics
• Course: MBG 1000
• Professor: Georgevander Merwe

Document Summary

23 diploid chromosomes: paired chromosomes 1-22, 2 sex chromosomes (xx or xy) Diploid = 2 sets of each chromosome (2n) Haploid gametes = one set of each chromosome. Genes orchestrate our physiology conception through adulthood. Development = process of forming adult from single celled zygote. In humans: new individuals form from the union of sex cells (or gametes, sperm from male and oocyte from female form zygote (fertiliezed oocyte) Cell division, growth and specialization produce an embryo. Form from cell division of germline cells: in ovaries + testis. Products of meiosis: meiosis has single dna perlication but 2 divisions of the nucleus. Meiosis i and meiosis ii: produces cells with half the # of chromosomes (n = haploid, 1 chromosome set) Necessary because: there r only 2 sex cells needed not 4. One copy of each pair from mom, one from dad. Variation = important in a changing environment. Evolution = genetic change in population over time.