Guided Reading on Mitosis and Cancer Chapter 8 1 Cells divide in both prokaryotes and eukaryotes Explain why cell division is important in both a prokaryote and a eukaryote Binary fission Prokaryotes and Mitosis Meiosis Eukaryotes both must have cell division in order to replace cells and create offspring 2 As a polymer DNA is far too long when stretched out to fit into the nucleus of a cell yet we know that all of our DNA resides in the nucleus How can this be Double helix 3 Your grandmother asks you What is a chromosome How might you explain what chromosome is A threadlike structure of nucleic acids and protein found in the nucleus of most living cells carrying genetic information in the form of genes a Are chromosomes present in all your cells all of the time 4 Compare and contrast chromosomes and sister chromatids Things to think about What makes them similar What makes them different When would you find a cell with chromosomes When would you find a cell with chromatids Every cell has chromosomes but a cell only has chromatids if it s going through cell division 5 What is the cell cycle When does the cell cycle start and when does it end Cell cycle an ordered sequence of events that extends from the time a cell is firtst formed from a dividing parent cell until its own division into two cells 6 What are the two main stages of the cell cycle and what happens in each Interphase G1 S G2 and Mitotic Phase Mitosis and Cytokinesis a At what point in the cell cycle does the cell perform its assigned function It performs it assigned function once the cell cycle control system triggers the next step in the cycle giving it a go ahead signal 7 Draw a cell in each of the 5 stages of mitosis interphase prophase metaphase anaphase telophase Label the chromosomes sister chomatids centromeres centrosomes and write a one sentence description of what is happening at each stage Interphase the period of cell growth when the cell synthesizes new molecules and organelles Prophase changes occur within both the nucleus and the cytoplasm Metaphase the mitotic spindle is fully formed with its poles at opposite ends of the cell Anaphase begins with two centromeres of each chromosome come apart separating the sister chromatids Telophase the cell elongation that started in anaphase continues Cytokinesis the division of the cytoplasm 8 Describe three different ways in which you could get cells to divide Binary fission dividing in half mitosis the nucleus and its content divide and are evenly distributed forming two daughter nuclei meiosis produces haploid gametes in diploid organisms 9 What is a cell cycle check point Cell cycle checkpoints are control mechanisms that ensure the fidelity of cell division in eukaryotic cells These checkpoints verify whether the processes at each phase of the cell cycle have been accurately completed before progression into the next phase Multiple checkpoints have been identified though some of them are less understood than others 10 How do growth factors promote cell division A growth factor is a protein secreted by certain body cells that stimulates other cells to divide 11 Define the following Tumor a swelling of a part of the body generally without inflammation caused by an abnormal growth of tissue whether benign or malignant Benign tumor a tumor that is not cancerous Malignant tumor a tumor that is malignant and tends to spread to other parts of the body Metastasis the development of secondary malignant growths at a distance from a primary site of cancer Carcinomas a cancer arising in the epithelial tissue of the skin or of the lining of the internal organs Sarcoma a malignant tumor of connective or other nonepithelial tissue Lymphoma cancer of the lymph nodes
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