Human Reproductive Technology Study Guide CHAPTER 1 genes A The 1st Week Fertilization and Pre Implantation Development o 1 The meeting of sperm and egg creates a unique combination of o 2 Cleavage Fertilization from a gamete egg sperm forming a zygote single cell embryo embryo genes chromosome genome combination of all DNA in each cell genotype what the indiv has nucleus membranous structure pronucleus nucleus of a gamete haploid 1 of each chromosome diploid 2 of each chromosome blastocyst 100 cell embryo cleavage process of early cell divisions blastocoel fluid filled cavity inner cell mass 30 34 cells bunched up in a ball inside the blastocoel embryonic tissue trophoblast remaining 66 70 cells that surround the ICM extra embryonic tissue ICM embryo trophoblast cells placenta uterus implantation pre implantation stages can occur outside the womb in vitro in a Petri dish Chorion extra embryonic tissues of the child decidua uterine lining of the mother zona pellucida embryos shell tubal pregnancy when the embryo implants before it reaches the uterus life threatening situation for the mother amniotic cavity where the embryo develops progesterone keeps the uterus soft low levels cause menstruation o 3 Implantation B Post Implantation The 1st Trimester 60 days or 8 weeks Gestation implantation to birth o 1 Gastrulation and Germ Layer Formation days 15 23 Germ layers type of somatic cell body germ cells next generation cells genes units of info in the DNA gene expression making use of the gene gene repression silencing not using gene mutations changes in the DNA sequence gastrulation stage at which differentiation of the embryo begins pluripotent cells embryo cells that have the potential to become any cell type of the body o 2 Identical Twins can no longer be formed after gastrulation begins o 3 Organogenesis Neurulation days 21 25 neural tube will eventually form the brain and spinal cord embryogenesis encompasses cleavage gastrulation and organogenesis also the developing offspring for the 1st 6 8 weeks following conception fetus embryo 28 30 weeks can be born and survive in the 3rd trimester 27 38 o 4 The Fetus weeks o 5 Sex Determination Autosomal chromosomes non sex chromosomes sex chromosomes gonads testes ovaries meiosis creates all other cells of the body mitosis produces two identical copies of the original cell retaining 2 of each chromosome primary sex characteristics gonads differentiate into testes and ovaries secondary sex characteristics external sex characteristics testosterone travels through the blood and binds to proteins on the surfaces of the cells in the body called testosterone receptors androgen insensitivity lack testosterone receptors Timetable Fertilization sperm determines whether XX or XY weeks 2 3 germ cells are formed in the gastrulating embryo weeks 5 6 germ cells migrate to developing gonads indistinguishable b t sexes weeks 7 8 primary sex characteristics weeks 10 14 secondary sex characteristics o 6 Consciousness the fetus generally shows its 1st positive EEG at week 25 7th month o 7 Birth Views o Japan 1st cry tribes N Ghana 7 days after birth Taiwan when a child is named 2 3 after birth Native Americans when 1st put to mothers breast Plato birth or physical separation from the mother Aristotle 40 days post conception in males 90 days in females Catholicism one celled zygote English common law 120 days when fetus moved Jewish crowning Islam soul is at 120 days abortion is only punishable if it s done w o the father s consent Hindu life begins at conception no abortion even to save mother s life CHAPTER 2 1 Gametogenesis Formation of Gametes o Gametes sperm and egg gametogenesis process of undergoing meiosis to make either sperm or eggs spermatocyte developing sperm matures continuously oocyte developing egg matured to eggs one at a time menstruation cycle 2 Fertilization Process by Which the Gametes Fuse o Localization sperm and egg finding each other penetration sperm must be able to penetrate zona pellucida prevention of polyspermy egg must prevent more than one sperm from entering fusion of genetic material initiating development calcium is released from storage compartments w in the egg leading to the 1st cell division IVF sterility Tubal blockages hormone therapy Moral Dilemmas of IVF when does life begin playing God when money becomes an ethical issue tough decisions extra embryos Prenatal and Pre Implantation Genetic Diagnosis accurate means to determine the genetic constitution of a child before birth Views on Sex Selection India dowry China sons support the parents Western family balance Catholic prohibits interference w procreation Protestant ok when there are medical benefits Islam unlawful split regarding medical cases Hebrew encouraged Medical community ok for family balancing USA no regulations parents have right to choose CHAPTER 3 Regenerative medicine regenerate damaged or diseased tissue stem cells are classified according to their developmental potential of different cell types that they can give rise to adult stem cells are those that maintain our tissues after the tissues have formed they only produce a limited of tissues committed stem cells ESCs have the potential to regenerate any tissue of the body pluripotent How do scientists make specific tissues w ESCs Conditioned medium where other cells have been grown and allowed to secrete factors defined culture conditions needed so that one can confidently and reproducibly produce the same tissue Safety issues The problem of immunological tissue rejection can be solved by making ESCs from the patient itself Oncogenes cancer causing genes teratoma tumor containing tissues from all 3 germ layers Religious Jewish an embryo w o blood Catholic IVF is prohibited Protestant diverse Islam 120 days Buddhist one cannot hurt any life CHAPTER 4 Genomic equivalence all cells in your body have the same DNA parthenogenetic activation eggs can be tricked into thinking they have been fertilized totipotent eggs that had potential to become an entire animal eugenics selecting a certain genetic constitution Reproductive cloning o Production of a complete copy of a human being intention of creating a human requires the implantation of the resulting embryo into a woman s uterus Therapeutic cloning o Production of a genetically identical blastocyst from which to extract genetically matched embryonic stem cells intention of helping a human requires that embryo develops in a blastocyst o Pros provide
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