BIOL 1107 1nd Edition Lecture 26 Outline of Last Lecture I Mitosis II Chromosome Mapping III Karyotype IV Interphase V Phases of Mitosis Outline of Current Lecture I Asexual v Sexual Reproduction II Mitosis v Meiosis III Meiosis I IV Meiosis II Current Lecture I Asexual v Sexual Reproduction Asexual reproduction mode of reproduction by which offspring arise from a single organism and inherit the genes of that parent only it is reproduction which almost never involves ploidy or reduction The offspring will be exact genetic copies of the parent except in the specific case of automixis Sexual reproduction Sperm Egg zygote II Mitosis v Meiosis Mitosis Identical cells Cell division is over Occurs in all organisms Makes everything other than sex cells III Meiosis Different cells cells divide again Sister chromatids line up Occurs is humans animals plants fungi Creates sex cells only Meiosis I Prophase I o this is the phase where chromosomes condense o mitotic spindle forms 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 IV o homologous chromosomes form chiasmata o two chromosomes from sister chromatids Metaphase I o Chromosomes line up on metaphase plate o Instead of individual chromosomes lining up we have pairs 4 chromatids lining up Anaphase I o Phase where chromosomes get pulled apart Telophase I Cytokinesis o Chromosomes condense o Haploid cells form o Decreased chromosomal content by half Meiosis II very similar to Meoisis I except with haploid cells Q How many unique gametes can a cell with two pair of chromosomes make 4 unique gametes Law of independent Assortment Mendel s chromosomes don t have preference as to where they line up Why bother Helps diversify population which helps in survival of population Q How can a cell end up with an incorrect of chromosomes Chromosomes do not separate correctly during mitosis or meiosis would be worse The older you get the higher the risk of getting child with down syndrome The different copies of chromosome 21 in a couple are shown to right How is Down syndrome detected o Karyotyping isolate chromosomes during cell division When would the best time be to isolate chromosomes for a karyotype Prophase Why would this be the best time Because you want them to be condensed but not overlapping
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