Lecture 2 Know that DNA is organized into structures called chromosomes o Chromosome A cellular structure carrying genetic material found in the nucleus of eukaryotic cells Each chromosome consists of one very long DNA molecule and associated proteins Be able to explain the significance of the coiling of chromatin o Coiling of chromatin leads to the formation of 2 sister chromatid which is what is pulled apart to begin mitosis duplication of the cell Be able to describe the multiple functions of cell division o o Growth o Development o repair Know that cell division results in genetically identical daughter cells o Through mitosis or meiosis Be able to describe the structure of a eukaryotic chromosome o o Histone proteins positive charged attach to DNA negatively charged and the DNA wraps around it o Nucleosomes are bead structures that is made of the coiled DNA and histones o After it is all coiled it is 2 sister chromatids that are pinched in middle by a centromere and the entire unit is a chromosome Be able to diagram the cell cycle indicating the timing of all processes o Timing Know that separation of sister chromatids occurs in Mitosis Know the major stages of Mitosis and what happens in each o Mitosis PPMAT o o Prophase chromatin condenses into discrete chromosomes mitotic spindle begins to form nucleolus disappears Prometaphase break down of nuclear envelope and spindle attaches to chromosomes Metaphase spindle is complete and chromosomes are attached and align in middle metaphase plate Anaphase chromosomes are separated at sister chromatids are being pulled apart to opposite poles Telophase daughter nuclei are forming Cell membrane closes in and splits the cell into 2 piece Now u have 2 separate cells each with half of the original DNA Be able to explain one potential evolutionary pathway leading to mitosis Be able to explain the experiment demonstrating that the spindle moves chromatids through tubule shortening Be able to explain the control of mitosis through CdK and cyclin o Cyclin protein that fluctuates in concentration to signal movement to o CdK A protein kinase that is active only when attached to a particular cyclin When its cyclin is attached together they form the maturation promoting factor MPF o Cdks signal the cell that it is ready to pass into the next stage of the checkpoints cell cycle o When cyclins are synthesized they act as an activating protein and bind to Cdks forming a cyclin Cdk complex This complex then acts as a signal to the cell to pass to the next cell cycle phase Eventually the cyclin degrades deactivating the Cdk thus signaling exit from a particular phase Know that cancer is the result of a failure of control of the cell cycle Terminology o Histone protein molecules around which DNA is tightly coiled in chromatin o Chromatin long strands of DNA found in the eukaryotic cell nucleus condense to form chromosomes o nucleosome bead like structures formed by histones and DNA o sister chromatid Two copies of a duplicated chromosome attached to each other by proteis at the centromere and sometimes along the arms While joined two sister chromatids make up one chromosome Chromatids are eventually separated during mitosis or meiosis II o centromere In a duplicated chromosome the region on each sister chromatid where they are most closely attached to each other by proteins that bind to specific DNA sequences this close attachment causes a constriction in the condensed chromosome An uncondensed unduplicated chromosome has a single centromere identified by its DNA sequence o o genome o somatic cell any body cells that is not a sex cell o gamete sex cells sperm and egg ovum o mitosis duplication of cells o meiosis duplication of sex cells G1 G2 and S phases cytokinesis o o o G1 the first gap growth phase of the cell cycle Interphase before DNA synthesis begins o G2 second gap growth phase after DNA synthesis occurs o S Phase the synthesis phase of cell cycle Portion of interphase during which DNA is replicated o Cytokinesis the division of the cytoplasm to form 2 separate daughter cells immediately after mitosis meisis Reading Chapter 16 320 322 review Chapter 12 Lecture 3 Know that a transcription factor is a molecule that can either stimulate or inhibit the expression transcription of a gene o Transcription factor A regulatory protein that binds to DNA and affects transcription of specific genes Know that a proto oncogene is a gene whose product stimulates growth i e the cell cycle o Proto oncogenes normal versions of cellular genes code for proteins that stimulate normal cell growth and division Be able to explain the three mechanisms through which a proto oncogene becomes an oncogene o Translocation transposition o Amplification Know that ras is the product of a proto oncogene and be able to explain how o Point mutation its mutation can lead to cancer o RAS MAKES PROTEIN THAT STIMULATES CELL CYCLE o Ras proto oncogene a protein that needs growth factor to activate a seris of protein kinases and causes normal cell division o Mutation in ras may not need G protein stimulation activates kinases on its own Ras becomes hyperactive o Know that p 53 is a tumor suppressor gene and be able to explain how a mutation that inactivates it can lead to cancer o P 53 PRODUCES A PROTEIN THAT INHIBITS THE CELL CYCLE o o Mutation in p53 cannot transcribe the proteins that inhibit cell cycle so the cells keep dividing Section 18 5 page 360 Chapter 15 Lecture 4 Gene Expression Reading 18 2 18 3 review chapter 11 and be able to perform the general objectives below only Be able to explain what gene expression means transcription and translation of genes o Gene expression the activation or turning on of a gene that results in transcription and the production of mRNA Genes are either expressed or repressed which dictates how a cell functions o Transcription RNA is produced from DNA o Translation protein synthesis Be able to explain that the differences in phenotype structure and function of cells with identical genomes is due to differences in gene expression o All cells have same genotype but different phenotype physical characteristics fucntions o Because of differentiation cells can specialize to do what is needed of them o ex Lung cells eye cells ear cells all have different functions and look different but have the same genotype Be able to explain that cell differentiation is largely a result of expression o Based on what genes are expressed cells are differentiated
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