ANTH 120 1nd Edition Lecture 5Outline of Last Lecture I. The Biological Basis of Life: Cells & DNAII. Cell BiologyIII. Structure of a CellIV. How genes synthesize within a biological structure?Outline of Current Lecture II. Cell DivisionIII. Mitosis And MeiosisIV. Genetic TerminologyV. Mendelian Laws of Inheritancea. Law of Segregationb. Law of Independent AssortmentCurrent LectureC e l l C y c l e1) Interphase  most growth of the cell occurs, protein synthesis, DNA duplication occursa. G1 Phase  primary and rapid cell growth, protein synthesisb. S Phase  DNA duplication, slow growth, Genome gets duplicated, X shape of chromosomes happen chromatids come togetherc. G2 Phase  final section of interphase, prepare for division, slow growth, DNA becomes condensed before it splits apart2) Mitotic Phase  Separation and division of the nucleusa. Mitosis  Nucleus Divides, 46 chromosomes get pulled apartb. Cytokinesis  Division of the cytoplasm and of the cell itselfc. G0 (G Zero)  Non-dividing period, helps carry out homeostasis i. Nerve cells are an example of a cell that can stay permanently in the G0 stageCell Cycle: G1 Phase  S Phase  G2 Phase  MitosisTwo Types of Cell Reproduction1) Mitosis: 2 Somatic Cellsa. Genetically identical daughter cellsb. Diploid  two sets of chromosomes (23 pairs = 46 total)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.2) Meiosis: 4 Gametes (4 sperm cells or 4 eggs)a. Haploid: one set of chromosomesb. Produces 4 non-identical daughter cells (sperms and eggs)Mitosis:- Split Somatic Cell & DNA into 2 identical daughter cells- 46 double stranded chromosomes go into Mitosis- Chromatids pull apart- 2 Daughter Cells are createdMeiosis Preparing for Sexual Reproduction:- Goal: 4 daughter cells (gametes) with variable genetic material- Reproductive Organs- Two Divisions Occuro Meiosis 1: 46 Chromosomes duplicate Homologous Pairs line up- Exchange of Genes- 2 New Cells- 23 double stranded chromosomes- Arms link up and exchange DNA, genes from mother and father are exchanged (cross over)- Pairs are separatedMeiosis 2:o 2 Cells and 23 Double Stranded Chromosomes line upo Sister chromatids pull aparto 4 Haploid cells with 23 chromosomesFertilization of Gametes- Meiosis: results in formation of gametes (with 23 chromosomes)- Fertilization is reunion of chromosomes o 23 +23 chromosomes = 46 total chromosomeso Two gametes = ZygoteHow are Genes inherited? / Why aren’t we a “blend”?Mendelian Genetics and InheritanceGregor Mendel: studied characteristics of garden pea plants through controlled experiments (1856-1868)Set the basic principles of genetics by documenting a particulate mechanism of inheritance Discovered laws that govern the passage of traits from one generation to the next, found thathappened in predictable ratiosHis work, in combination with that of Charles Darwin, set the foundation for the Theory of EvolutionGarden Pea Plants:o Normally pea plants are self fertilizingo Cross pollinated thousands of plants himself over 8 yearso Traits: flower color, pea color, plant heighto He created many clones of these pea plants Observing flower color…o Cross-bred pure strains o Purple flowers x White flowers  all plants had purple flowerso Crossed PURPLE F1 flowers: 3:1 Purple Flowers : White FlowersConcluded: traits are caused by different versions of the SAME GENEo Gene: Flower Color o Alleles -PURPLE allele -WHITE alleleDominant Vs. Recessive Why aren’t the flowers purple & white… a blend? One of the alleles is dominanto It makes the expression of the other alleleo It is fully expressed in the phenotype (appearance of the organism)o Only need one allele for full expression  Heterozygote (1 dominant and 1 recessive allele) Homozygous dominant (2 dominant alleles) White flowers allele is completely masked, recessive alleleo Need 2 alleles for full expression in the phenotype HomozygousImportant TermsDiploid: a pair of chromosomesHomozygos DominantHomozygos RecessiveHeterozygosA plant with purple flowers:o Possible Genotypes: TT Tto Phenotype Purple Flowers A plant with white flowers:o ONLY Genotype: to Phenotype White flowersDominance is NOT frequencyHuntington’s Disease Lethal dominant allele Expressed in the heterozygote in midlifeMendel’s Law of InheritanceFirst Law  “Law of Segregation” Gametes can only carry one allele Progeny has an EQUAL chance of receiving either allele Punnet Squares  Paired alleles separate during gamete production (meiosis). Progeny has an EQUAL chance of receiving either allele 3:1  Phenotypic RatioSecond Law  “Law of Independent Assortment” Genes for different traits separate from each other independently during meiosis Traits are independent because they are carried on different chromosomes Mendel followed 2 traits (genes): color and shapeo Gene: Color and Shapeo Allele #1: Yellow (Y Dominant) and Round (R) dominanto Allele #2: Green (y) recessive and Wrinkled (r) recessivePeas could be ANY combination! Traits are NOT linked.DiHybrid Cross F1 x F12 Heterozygous Mendelian Trais: Each gene has a distinct biological