I. Why do Cells Divide?A. The Cell TheoryB. The Start of LifeC. Potential ProblemsII. Reproductive StrategiesA. AsexualB. Asexual in EukaryotesC. SexualD. ProkaryoticIII. Chromosome StructureA. Chromosomes in OrganismsB. ChromatinC. ChromatidIV. The Cell CycleA. InterphaseB. MitosisC. CytokinesisBIO 105 1st Edition Lecture 6Outline of Current Lecture I. Why do Cells Divide?A. The Cell TheoryB. The Start of LifeC. Potential ProblemsII. Reproductive StrategiesA. AsexualB. Asexual in EukaryotesC. SexualD. ProkaryoticIII. Chromosome StructureA. Chromosomes in Organisms B. ChromatinC. ChromatidIV. The Cell CycleA. InterphaseB. MitosisC. Cytokinesis 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.Current Lecture*Tucker’s Take Home Points!-IMC-PMATI. Why do Cells Divide?a. The Cell Theoryi. all cells come from other cellsii. cells grow in order to reproduce1. cells reproduce in order to maintain homeostasis and repair the bodyb. The start of lifei. cell division is required for lifeii. We begin as a zygote, just 1 cell!1. Our cells will divide 10,000,000,000,000,000 times in our livesc. Potential Problemsi. Cancer – A Group of Diseases 1. Deregulation of cell division2. ½ of males and 1/3 of females will be diagnosed in their lifetimeII. Reproductive Strategiesa. Asexuali. One Parentii. Genetically Identical Offspringb. Asexual in Eukaryotesi. Uses Mitosis1. Prosa. No mate requiredb. Biologically “cheaper”c. Good in stable environments2. Consa. Limits adaptation and evolutionb. Offspring is less able to adapt in an unstable environmentc. Sexuali. Two Parents1. Gametes (sperm, ova)ii. Unique Offspringd. Prokaryotici. Binary Fission (literal translation: two split apart)ii. Simple Chromosomes1. Simple divisioniii. 3 Steps1. Cell Copy DNA2. Growth3. DivisionIII. Chromosome Structurea. Chromosomes in Organisms i. Eukaryotic Chromosomes1. Linear2. Larger3. More Complex4. More genes on each chromosomeii. Human Chromosomes1. 46 Chromosomes2. 23 Homologous Pairsa. 1 pair of sex chromosomesi. Female: XXii. Male: XYb. 22 Pairs of Autosomes3. Chromosomes are similar NOT identical4. Diploid: 2 of each chromosomes (2n)5. Haploid: 1 of each chromosomes (1n)6. Where does each chromosome come from?a. Each Parent.b. Chromatini. Chromosomes are 1 long DNA molecule, wound with proteins. This is chromatin.c. Chromatidi. The ends of the “X” are the “sister chromatids” when they are attached. ii. Sister chromatids are IDENTICAL. iii. They are joined in the middle by centromeres.IV. The Cell Cycle (Growth and Division Phases)a. Interphase: DNA replication and growthi. Active Phaseii. Longest part of the Cycle (90% of life)iii. Parts1. G1: Growth2. S: Synthesis (copying) chromosomes3. G2: Growthiv. Review Figure 8.4b. Mitosis: Division of the Nucleusi. Produces identical “daughter Cells”ii. 3 Steps: Copy, Separate, Divideiii. 4 Phases1. Prophasea. Chromosomes become coiled and visibleb. Mitotic Spindle (guide separation of sister chromatids)c. Nuclear envelope breaks apartd. Review figure 8.5-22. Metaphasea. Chromosomes align on metaphase plateb. Review figure 8.5-73. Anaphasea. Sister Chromatids Separatei. Spindle fibers pull apart the chromatids, but they also push against each other to elongate the cellb. Review Figure8.5-74. Telophasea. Chromosomes uncoil and disappearb. Mitotic spindle disappearc. Nuclear envelope formsc. Cytokinesis: Division of Cell (and organelles)i. Simultaneous with telophaseii. Cytoplasm (cytosol and organelle) is dividediii. Review 8.5-7iv. Difference in animals vs. plants1. Cytokinesis in animal cellsa. Cleavage Furrowi. Band of actin (microfilament cytoskeleton) pinches apart cells2. Cytokinesis in Plant cellsa. Cell Platei. Vesicles carry membrane into middle line and create 2 membranes. This is the cell Plate.3. Compare and Contrast Mitosis and Meiosis online resource assignment. Assignment due