LIFE 102 (003): Attributes of Living Systems Study Guide Exam 3Chapter 14: Classical Genetics IChapter 15: Classical Genetics IIChapter 16: The Molecular Basis of InheritanceChapter 17: From Gene to Protein (very important!!!!)LIFE 102 (003): ATTRIBUTES OF LIVINGSYSTEMS STUDY GUIDE EXAM 3Chapter 12: Mitosis Why do cells divide? Organismal reproduction, growth and repair. Difference betweenasexual & sexual cell reproduction? Asexual: daughter cells are identical copies ofmother cell (clones)[mitosis, in all organism], sexual: daughter cells are not identicalcopies of mother cell[meiosis, Eukaryotes only]. Where do each occur? Meiosis:gonads(ovaries and testes), Mitosis: Eukaryotic cells. What are the primary steps ineukaryotic cell division? Cell grows and duplicates organelles, DNA is duplicated, DNAis divided to the two poles of the cell, Cell divides (cytoplasm separates) to form twocells of approximately equal size. What features of eukaryotic cells make thiscomplicated process necessary? How is DNA organized in a eukaryotic cell? Multiplechromosomes. What is the genome? Living things genetic material. What is a chromatin?What eukaryotic chromosomes are made of, complex of DNA, and associated proteinmolecules. What is the cell cycle? a process in which a cell grows and divides to create acopy of itself. What events occur at each step in the cell cycle? Cell growth and DNAreplication, Mitosis: division of the nucleus, Cytokinesis: division of the cytoplasm andformation of two daughter cells. At which step(s) of the cell cycle does the cell commit tocell division? G1, G2, M phases. Non-dividing cells are in what stage of the cell cycle?G0 phase. What events occur in each phase of mitosis? Interphase: the cells grow, andDNA is copied, Prophase: The chromosomes become more visible (stringy to rod like),nucleoli disappear, each duplicated chromosome appears as two identical sisters, mitoticspindle begins to form(composed of centrosomes and microtubules extend from them)aster(shorter microtubules) extend from centrosomes, centrosomes move from each other.Prometaphase: nuclear envelope fragments, centrosome invade nuclear area,chromosomes more condensed, each of two chromatids of each chromosome now has akinetochore(specialized protein structure located at the centromere), some microtubulesattach to kinetochore(becoming kinetochore microtubules); jerk the chromosomes backand forth, nonkinetochore microtubules interact with those from the opposite pole of thespindle. Metaphase: longest stage of mitosis, centrosomes are not opposite poles of thecell, chromosomes centromeres lie on metaphase plate(middle of spindles), for eachchromosome the kinetochores of the sister chromatids are attached to kinetochoremicrotubules coming from opposite poles. Anaphase: shortest stage, sister chromatidssplit apart(each chromatid becomes a full chromosome), separated daughterchromosomes move toward opposite ends(move from centromere region first), cellselongates as nonkinetochore microtubules lengthen, two ends of the cell have equal andcomplete collections of chromosomes. Telophase: two daughter nuclei form in the cell,nuclear envelope come from fragments of the parent cell’s nuclear envelope and portionsof endomembrane system, nucleoli reappear, chromosomes less condensed, division ofone nucleus into two genetically identical nuclei. Cytokinesis: division of the cytoplasm,two daughter cells appear shortly, in animals; cytokinesis involves formation of acleavage furrow, which pinches the cell in two. What is the role of the mitotic spindle?Pulls sister chromatids apart, movement. What are centrioles: (2)cylinders that give offthe microtubules. What are centrosomes: important during cell division, function as amicrotubule-organizing center. What centromeres: region where two sister chromatidsmeet. What events occur during Cytokinesis: *look at mitosis events*. How doescytokinesis differ in plant and animal cells? Animal: cleavage furrow, shallow groove incell surface near the old metaphase plate, produce daughter cells. Plants: no cleavagefurrow, forms cell plate that separate, new cell walls arise from contents of cell plateforming between daughter cells. How is cell division regulated? There are several thingsthat govern when and if a cells commits to the process of cell division. These include:nutrient availability, presence of growth factors, cell density (whether cells are in contactwith neighbors on the tissue culture plate) and cell size. What factors affect cell division?Nutrient availability, growth factors, cell density, cell size. What is density-dependentinhibition? Crowded cells stop dividing. Do cancer cells exhibit density-dependentinhibition? No. How are cancer cells different from “normal” cells? Do not stop dividing,stop dividing at random points in the cell cycle, and go on dividing indefinitely if givenendless supply of nutrients. Where in an organism would you find mitosis occurring? Incells that are growing or being repaired.Chapter 13: MeiosisWhat is asexual reproduction? (Mitosis)Daughter cells are identical copies of mothercells (clones). What is sexual reproduction? (Meiosis)Daughter cells are not identicalcopies of mother cells. What are gametes? Reproductive cells (egg and sperm). Whatare germ cells? Another name for gametes. What are the characteristics of somatic cells& gametes? Somatic cells: body cell, diploid; Gametes: germ cells, haploid. Steps insexual life cycle: Meiosis occurs in germ cells during the production of gametes, whichundergo no further cell division prior to fertilization, after fertilization, the diploid zygotedivides by mitosis, producing a multicellular organism that is diploid. In meiosis I, thehomologous chromosomes separate. In meiosis II, the sister chromatids separate. Whatare sister chromatids? two identical copies of a chromatin connected by a centromere.What are homologous chromosomes? two different copies of the same chromosomethat diploid organisms inherit, one from each parent. Meiosis I: Prophase I:Chromosomes condense, pair up, aligned gene by gene, crossing over is completed,homologous pairs are tightly together by proteins along length, connected