Chapter 29 - Development and Inheritance

Chapter 29 - Development and Inheritance - Chapter 29...

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Chapter 29 – Development and Inheritance Development :  Gradual   modification   of  anatomical  structures   and  physiological   characteristics   from   fertilization   to  maturity  Differentiation: creation of different cells required in development; occurs through selective changes in genetic activity as  development proceeds, some  genes  turned off, others turned on Fertilization (Conception) - when development begins Embryological Development  occurs during first 2 months after fertilization Fetal Development - begins at start of ninth week and continues until birth Prenatal Development  - embryological and fetal development stages Postnatal Development - starts at  birth aging  process begins Inheritance - transfer of genetically determined traits from generation to generation  Genetics - study of mechanisms responsible for inheritance Fertilization: fusion of 2  haploid   gametes , 23  chromosomes each zygote  46 chromosomes Spermatozoon - delivers  paternal  chromosomes to fertilization site; must travel relatively large distance so it is small, efficient  Gamete embryo for a week; occurs in  uterine tube  within a day after  ovulation Secondary oocyte  travels a few cms while  Sperm  must cover distance between  vagina ampulla Capacitation must occur before spermatozoa can fertilize secondary oocyte; occurs with contact with secretions of seminal  Hyaluronidase  enzyme breaks bonds between  follicle cells Acrosin is a proteolytic enzyme required to reach oocyte ; Acrosomal Caps corona radiata, zona pellucida, toward oocyte surface Oocyte Activation :  contact & fusion of cell membranes of sperm & oocyte; meiosis II , becomes mature  ovum Polyspermy: fertilization by more than one sperm is prevented by cortical reaction ; cortical reaction releases enzymes that  Female Pronucleus : nuclear material remaining in ovum after oocyte activation Male Pronucleus: swollen nucleus of spermatozoon - migrates to center of cell Amphimixis: fusion of  female & male pronucleus; moment of conception cell becomes a zygote with 46 chromosomes  Cleavage: series of cell divisions that produces daughter cells Differentiation: involves changes in genetic activity of some cells but not others Induction: cells release chemical substances that affect differentiation of other embryonic cells; can control highly complex 
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This note was uploaded on 07/13/2011 for the course BIOL 2401 taught by Professor Watson during the Summer '10 term at Richland Community College.

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Chapter 29 - Development and Inheritance - Chapter 29...

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