Objectives for Exam 1 PCB 3063 Spring 2016 Mitosis and Meiosis Lectures 1 Chapter 2 Of basic importance in this material is to know the essential differences between mitosis and meiosis what homologous chromosomes are and how they behave in mitosis and meiosis Know the important events that occur in meiosis and understand how meiosis differs from mitosis Homologous Chromosomes Homologous chromosomes are similiar but not identical Each carries the same genes in the same order but the alleles for each trait may not be the same In garden peas for example the gene for pod color on the maternal chromosome might be the yellow allele the gene on the homologous paternal chromosome might be the green allele Understand the concept of the cell cycle and know what happens pens during S phase The interphase portion of the cell cycle is relatively long compared to mitosis Interphase consists of three stages first gap G1 synthesis S and second gap G2 The cell replicates DNA only in the S phase Before the cell can transition from G1 to S it must clear the G1 checkpoint The cell will only enter the S phase if the DNA is undamaged and the cell has grown sufficiently in the G1 stage When a cell passes through the checkpoint it overcomes p16 repression by building other proteins that allow the S phase to begin Be able to name the stages of mitosis and know what events take place in each Know what sister chromatids are A sister chromatid refers to either of the two identical copies chromatids formed by the replication of a single chromosome with both copies joined together by a common centromere In other words a sister chromatid may also be said as one half of the duplicated chromosome Understand the term diploid and haploid and know what homologous chromosomes are how they are similar to each other and how they differ from nonhomologous chromosomes see above for homologous chromosomes Homologous chromosomes are the chromosomes which contains alleles for same type of genes one from sperm and one from egg or can be called similar But Non Homologous chromosomes are chromosomes that contains alleles for different type of genes Exceptions Sex Chromosomes are homologous chromosomes but do not carry the same genes Some organisms are Haploid 1n one copy of every chromosome Fungi some algae and protozoans Most Organisms are Diploid 2n two copies of every chromosome Be able state how many chromosomes and pairs of homologous chromosomes are present in cells of a given diploid number that are undergoing meiosis Understand the terms tetrad chiasmata crossing over and recombination Skill be able to solve genetics problems similar to those in the first homework assignment related to chapter 2 Review of Mendel s Principles and Probability in Genetics Lectures 2 3 Chapter 3 Be able to state Mendel s postulates Random Segregation and Independent Assortment and understand their significance 1 Each trait is controlled by a pair of factors GENES 2 When 2 different factors for a trait are present in an individual one is DOMINANT and one is RECESSIVE ALLELES alternate forms of a gene 3 During gamete formation the paired factors SEGREGATE RANDOMLY 4 MENDEL S FOURTH POSTULATE Or MENDLE S LAW OF INDEPENDENT ASSORTMENT Genes for different traits are inherited independently they assort independently into the gametes Know and be able to use the terms phenotype genotype homozygous heterozygous dominant recessive allele true breeding or pure breeding parental generation F1 generation F2 generation F1 hybrid monohybrid cross dihybrid cross PHENOTYPE the physical expression of a trait GENOTYPE the genetic makeup of an individual HOMOZYGOUS both alleles for a trait are the same HETEROZYGOUS two different alleles for a trait are present A MONOHYBRID cross represents the inheritance pattern of a single trait whereas a DIHYBRID cross represents the inheritance patterns of two traits that are linked F1 generation is the offspring of the parental generation p generation F2 generation offspring of the F1 generation grandchildren to p generation F1 hybrid result of true breeding p generation homozygous breeding resulting in heterozygous generation chapter 3 Be able to read a genetic family tree for humans pedigree and be able to determine from the tree whether a particular trait is inherited as a dominant or a recessive trait Be able to solve genetics problems involving X linked genes and be able to identify human pedigrees that display an X linked recessive or X linked dominant pattern of inheritance To understand how to read a pedigree either review the powerpoint on Blackboard or check out one of these videos o https www youtube com watch v Ir1t9awmUl4 o https www youtube com watch v Ztzi6pAh5M Be able to solve genetic inheritance probability problems using the product law and the sum law for crosses resulting in up to three progeny The probability of two or more independent outcomes occurring PRODUCT RULE together is equal to the product of their individual probabilities Sum Rule combinations of independent events is the sum of the probabilities for each combination The probability that an outcome can occur through two or more different o https www youtube com watch v y4Ne9DXk Jc Understand how Chi Square is used to determine whether genetic data fits predicted theoretical ratios and be able to solve probability problems using Chi Square The Null Hypothesis there is no difference between the observed and expected outcomes the difference is small enough that it could have happened by random chance If p 0 05 the outcome is not due to chance If p 0 05 the outcome is concluded to be due to chance o https www youtube com watch v WXPBoFDqNVk Extension of Mendelian Genetics Lectures 4 5 Chapter 4 Know the terms codominant and partially dominant be able to explain how they differ from each other and from dominant and recessive traits Be able to solve genetics problems involving codominant and partially dominant traits similar to those in homework 2 Incomplete or Partial Dominance neither allele is dominant phenotype of heterozygote is intermediate Example Flower Color carnations camellias snapdragons Codominance both alleles are expressed phenotype of heterozygote is a combination of the two homozygotes Multiple Alleles More than two alleles for a given trait examples o ABO blood groups o Coat color in mammals o Human hemoglobin types o Cystic fibrosis A and B are glycolipids on the surface of red blood cells IA and IB code for
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