tailieunhanh - Lecture Biology: Chapter 13 - Niel Campbell, Jane Reece

Chapter 13 - Meiosis and sexual life cycles. This chapter distinguish between the following terms: somatic cell and gamete, autosome and sex chromosomes, haploid and diploid; describe the events that characterize each phase of meiosis; describe three events that occur during meiosis I but not mitosis; name and explain the three events that contribute to genetic variation in sexually reproducing organisms. | Chapter 13 Meiosis and Sexual Life Cycles Overview: Variations on a Theme Living organisms are distinguished by their ability to reproduce their own kind. Genetics is the scientific study of heredity and variation. Heredity is the transmission of traits from one generation to the next. Variation is demonstrated by the differences in appearance that offspring show from parents and siblings. Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings Inheritance of Genes Genes are the units of heredity, and are made up of segments of DNA. Genes are passed to the next generation through reproductive cells called gametes (sperm and eggs). Each gene has a specific location called a locus on a certain chromosome. Most DNA is packaged into chromosomes. One set of chromosomes is inherited from each parent. Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings Comparison of Asexual and Sexual Reproduction In asexual reproduction, one parent produces genetically identical offspring by mitosis. A clone is a group of genetically identical individuals from the same parent. In sexual reproduction, two parents give rise to offspring that have unique combinations of genes inherited from the two parents. Video: Hydra Budding Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings Concept : Fertilization and meiosis alternate in sexual life cycles A life cycle is the generation-to-generation sequence of stages in the reproductive history of an organism. Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings Sets of Chromosomes in Human Cells Human somatic cells 2n (body cells other than a gamete) have 23 pairs of chromosomes. A karyotype is an ordered display / picture of the pairs of chromosomes from a cell. Mitosis / Metaphase. The two chromosomes in each pair are called homologous chromosomes, or homologs. Chromosomes in a homologous pair are the same length and carry genes / . | Chapter 13 Meiosis and Sexual Life Cycles Overview: Variations on a Theme Living organisms are distinguished by their ability to reproduce their own kind. Genetics is the scientific study of heredity and variation. Heredity is the transmission of traits from one generation to the next. Variation is demonstrated by the differences in appearance that offspring show from parents and siblings. Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings Inheritance of Genes Genes are the units of heredity, and are made up of segments of DNA. Genes are passed to the next generation through reproductive cells called gametes (sperm and eggs). Each gene has a specific location called a locus on a certain chromosome. Most DNA is packaged into chromosomes. One set of chromosomes is inherited from each parent. Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings Comparison of Asexual and Sexual Reproduction In asexual reproduction, one parent .