Exam 2 - 1) How are activated receptor tyrosine kinases...

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1) How are activated receptor tyrosine kinases deactivated? A. Phosphodiesterases remove phosphate groups from the activated receptors. B. Phosphatases remove phosphate groups from the activated receptors. C. Membrane pumps return calcium ions to storage. D. cAMP and cGMP are converted to inactive AMP and GMP. 2) C 6 H 12 0 6 (glucose) + 6 O 2 = 6 CO 2 + 6 H 2 O Where is the majority of the water in this reaction produced? A. glycolysis B. Krebs cycle C. fermentation D. electron transport chain 3) Researchers used fluorescent labels to make the chromosomes and the microtubular structures fluorescence in dividing cells. When anaphase begins (centromeres split), they photobleached a section of microtubules between the chromosomes and the centrosome. As chromosomes moved toward the poles of the daughter cells, the photobleached sections of the microtubules remained stationary. This suggests that: A. The microtubules elongate at the kinetochore end and shorten at the centrosome end. B. The microtubules slide with respect to each other, effectively shortening the microtubules without depolymerizing the actual fiber. C. The microtubules shorten at their kinetochore end. D. The microtubules are of constant length; centrosomes move farther apart to separate chromosomes. 4) Energy from sunlight can excite electrons, kicking them out of their orbitals and creating free radicals. Carotenoids, one of the pigments present in most chloroplasts, can stabilize these free radicals. Which of the following statements is true? A. Carotenoids probably have a protective function in the cell. B. Once chloroplasts are destroyed, the free radicals will destroy the cell. C. Other pigments (besides carotenoids and chlorophyll) are essential for the health of a plant cell. D. Carotenoids communicate directly with the immune system of plants.
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Use fiqure and table for questions 5 & 6 signal molecule l G-protein-linked l receptor activated , phospholipase C- β A. PI 4,5-bisphosphate [PI(4,5)P 2 ] I I diacylglycerol activated G q a subunit inositol 1,4,5 trisphosphate --' (IP3) (ill@) 2+ Qjl@)Ca open 1P3-gated Ca 2 +- release channel lumen of endoplasmic reticulum When cells are stimulated with the signal molecule (Signal), protein kinase C activity is elevated, which can be measured. In addition, protein kinase C activity can be activated by simultaneous treatment with two drugs. One is phorbol ester, which is a membrane permeable analog of DAG. The other is a Ca++ ionophore. You are given two compounds (A and B) that inhibit activation of protein kinase C activity by the Signal. You treat cells with these compounds in various combinations with Signal, DAG or the Ca++ ionophore and measure protein kinase C activity. Here are the data: Treatment protein kinase C activity (arbitrary units) None Signal Signal + phorbol ester Signal + Ca++ ionophore Phorbol ester + Ca++ ionophore 1 20 23 24 25 Signal + drug A Signal + phorbol ester + drug A Signal + Ca++ ionophore + drug A Phorbol ester + Ca++ ionophore + drug A
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Exam 2 - 1) How are activated receptor tyrosine kinases...

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