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Why is chromosomal DNA tighly wound during meiosis but not during interphase?
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During interphase the DNA needs to be able to be transcribed
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Bacteria typically have ______ which eukaryotes have _______ (types of chromosomes)
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One circular chromosome, many linear chromosomes
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Compare the processes and outcomes of mitosis and meiosis
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Mitosis: 2N, 1D, 1S, 2N
meiosis: 2N, 1D, 2S, 1N
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One of the differences between mitosis and Meiosis I is...
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Homologous chromosome pairs synapse during meiosis, but not mitosis
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Why is a signal transduction pathway that involves multiple steps in some ways better than a signaling pathway that uses direct coupling?
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Both B and C...because a pathway with multiple steps can amplify the signal; because a pathway with multiple steps can be couple to multiple effectors instead of just one
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Chemical messengers that are synthesized in response to a local stimulus and diffuse to neighboring target cells are:
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Paracrine signals
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Remember that bacteria produce restriction enzymes in their cytoplasm as a defense strategy against infection by bacteriophage. A bacterium's chromosomal DNA does not get chopped up by the restriction enzymes because...
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The bacterial DNA is chemically modified, which protects it from being cut by the restriction enzymes
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If I wanted to close the gene encoding a protein that was found to be defective in skin tissues of a patient with a certain disease, why might it be smart to use a CDNA library made from skin cells rather than a cDNA library made from kidney epithelium?
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Both A and C....because cDNA libraries include copies of only the genes expressed in a given cell type, and because the CDNA library from kidney epithelium MIGHT not include the CNDA encoding the protein of interest.
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Which of the following could be used for detection of genetic disorders?
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All of the above
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Why are rapidly dividing cells particulary sensitive to DNA damage by chemical mutagens or radiation?
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Because DNA repair enzymes need time to fix the damage before the cell divides.
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During the response to infection by invading bacteria, how does the production of circulating (secreted) antibodies against a protein found on the surface of the bacterium help the body to clear the bacterial infection?
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Binding of antibodies to the surface of the bacterium helps macrophages enguld the bacteria
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Immunoglobins (the B-cell receptor or secreted antibodies) are composed of _____, which are made of _______ chains
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Tetramer, two heavy and two light
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According to the clonal expansion (or clonal selection) theory,
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An antigen stimulates the proliferation of a specific group of B-cells
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What tissue/organ is NOT affected directly by cystic fibrosis?
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Air-exchanger surface on the lung
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What type of therapy would be of greatest benefit to a CF patient with either the delta F508 or the N1202K genotypes?
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B and D....drugs that promote proper folding and processing of the mutant protein; drugs that block the hyperactive sodium channel
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