ZOL 141 1st Edition Lecture 6Outline of Last Lecture I. CELL CYCLEa. Interphaseb. Mitosisc. CytokinesisII. Mitosis is Essential to growthIII. Genetic Diseases Associated with problems of cell divisionOutline of Current Lecture II. Review of Mitosis phasesIII. Meiosisa. Diploidb. HaploidCurrent LectureProphase- Chromosomes condense- Chromosomes randomly located in nucleusMetaphase- Chromosomes align at equatorAnaphase- Sister chromatids break apart and move to opposite poles of cellTelophase and Cytokinesis- Two daughter cells with two chromosomes each (stick form)Suppose human sperm and eggs were produced by mitosisHow many chromosomes would each sperm or egg have? 46What would happen after fertilization? 92 chromosomesHow many chromosomes would zygote have?Fertilization: process when sperm and egg fuseZygote: fertilized egg that develops into an individualWhy can your body not use mitosis to make sperm or eggs? Chromosome set must be reduced by halfMeiosis:Cell division which will reduce the number of chromosomes by half- Takes place in germ cells to produce gametes (sperm and egg)- Diploid cells become haploidDiploid vs Haploid- Diploid (2n): somatic cellso Somatic: “normal” human cell:o 46 chromosomes OR 23 pairso diploid, 2no two chromosome sets: one from mom, one from dado each chromosome is represented twice as a member of homologous pair homologous chromosomes have identical loci, one from dad, one from mom- Haploid (n): gameteso i.e., egg or sperm: 23 chromosomes, no pairs!o Haploid, no One chromosome seto Each chromosome represented onceo
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