Transcript Chapter 10
Cell Division Cell cycle and Mitosis: Chapter 10 Not responsible for: Figure 10.3 & related text on proteins that control chromosome separation and septum formation 10.7 Control of the cell cycle. This section covers more of the molecular details than you will be responsible for; however, we will cover the concept of cell cycle checkpoints, oncogenes and tumor suppressor genes as related to cancer Question Cell Reproduction 1 Why is it important to understand the processes of cell replication? Diversity & evolution Cancer Birth defects Basal cell carcinoma Reproductive biotechnology eukaryotic prokaryotic Question Cell Reproduction 2 What are the characteristics of cell division in Prokaryotes? Simpler structure No nucleus Single chromosome Binary fission Cell Reproduction 3 Chromosome structure in eukaryotes Structure of chromosomes … in nondividing cells … in dividing cells Supercoiling Question Cell Reproduction 4 What are homologous chromosomes? Homologous Chromosomes: -- one derived from each parent -- possess same genes, although genetic information in gene may be different = “alleles” How many homologous chromosomes do different organisms possess? humans: 2N = 46 N= haploid # of chromosomes goldfish: 2N=94 crayfish: 2N = 200 Autosomes vs sex chromosomes Question Cell Reproduction 5 What is the cell cycle? What are the stages and events? Mitosis G1 G0 S G2 Question Cell Reproduction 6 What are the steps of mitosis? When does mitosis occur? What are the stages of mitosis? prophase prometaphase metaphase anaphase telophase Cytokinesis Animal cell mitosis Cell Reproduction 7 McGraw-Hill mitosis What happens during prophase? Chromosome condensation Spindle apparatus Centrosomes kinetochore What happens during prometaphase? Nuclear membrane Spindle attachment Kinetochores Question Cell Reproduction 8 …Metaphase …Anaphase Filaments ‘pull’ and “push’ Question Cell Reproduction 9 Telophase and cytokinesis What happens during telophase? What causes cytokinesis to occur? Does cell division in plants and animals differ? Plant cell mitosis Cell Reproduction 10 Homework assignment: 5 points: due next class For a cell where 2N=6, draw a series of diagrams showing the chromosomes moving through the stages of mitosis. In one of the diagrams clearly label: -- a pair of homologous chromosomes -- two sister chromatids -- spindle fibers -- centrosomes and -- position of a kinetochore Label all stages (prophase, prometaphase, metaphase, anaphase and telophase) Make diagrams large, clear and neat Advanced artistry is not required, but drawings of supercoiled chromosomes and spindle fibers must show reasonable effort to accurately represent these structures. not x Question Cell Reproduction 11 What is the difference between a ‘tumor’ and ‘cancer’? Benign vs malignant tumors Metatasis Primary vs secondary tumors The angiogenesis problem Why are tumors and cancer so harmful? Angiogenesis and Metastasis Cell Reproduction 12 What causes a tumor to grow? Loss of control of cell division What are Protooncogenes? -- proteins they code for act as molecular ‘switches’ for cell division Oncogene = mutated protooncogene -- ‘switch’ is locked in the ‘on’ condition What are Tumor Suppressor Genes? -- proteins they code for stop abnormal cells from reproducing -- damaged DNA -- cell cycle ‘checkpoints’ Mutated tumor suppressor gene -- “Stop” signals do not work Other mutations cause tumorous cells to spread as a cancer = “Metastasis” Cell Reproduction 13 Stem cells and cloning What are stem cells? Embyonic vs somatic How is cloning performed? Mitotic Waltz Cell Reproduction 14