Week 5 LS2 – Flashcards
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The CORRECT sequence of steps in the eukaryotic cell cycle is:
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G1-->S phase-->G2---> mitosis--->cytokinesis
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A skin cell in G2 of interphase has _____ as much DNA as it had in G1
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twice
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The CORRECT sequence of steps in the M phase of the cell cycle is:
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prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis
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In which phase of mitosis do spindle microtubules shorten?
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anaphase
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Which of the following is NOT true about gametes?
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True: They have half as many chromosomes as a somatic cell in of the same individual, they are called egg and sperm cells in animals, they are made during meiotic division, they fuse to form a new organism during fertilization
NOT TRUE: they are genetically identically to other gametes during meiotic division
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Which major checkpoint delays the cell cycle when DNA replication is incomplete?
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G2
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The amount of _____ is fairly constant throughout the cell cycle, but the amount of _____ varies.
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cyclin-CDK complexes are fairly constant.. they are just sometimes inactive
The amount of DNA varies
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The S cyclin-CDK complex
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controls the cell cycle during S and G2 phase, triggers DNA synthesis during S phase, prevents a second round of DNA synthesis
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p53
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is an example of a tumor oppresor
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Four events must occur for cell division
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Reproductive signal: to initiate cell division
Replication: of DNA
Segregation: distribution of the DNA into two cells
Cytokinesis: separation of the two cells
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Who identified the first growth factors?
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Allan Lipton and Nancy Kohler through experiments with blood. It was found that platelets are responsible for blood clotting. So they tried purifying cells with purified platelet proteins. This led to the development of PDGF(platelet derived growth factors)
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Cells must decide if they should follow through with the cell cycle. They ask themselves if..
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Is the cell big enough?
Is there room?
Growth factors?
Is the DNA replicated?
