Bio exam 4 2009

Bio exam 4 2009 - 1 2 3 4 5 6 Biology 181R Exam#4 From the...

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Biology 181R Exam #4 1. From the perspective of the cell receiving the message, the three stages of cell signaling are ________________. a. The paracrine, local and synaptic stages b. Signal reception, signal transduction, and cellular response c. Signal reception, nucleus disintegration, and new cell generation d. Signal reception, cellular response, and cell division e. Paracrine, autocrine and endocrine stages 2. Cells use different signaling strategies to achieve different goals. In hormonal (endocrine) signaling ____________. a. Numerous cells can receive and respond to a signal produced in their vicinity b. Special molecules are passed through cell junctions c. The signal can be directed to a very specific target because a narrow space separates the target cell from the transmitting cell d. Specialized cells release hormone molecules into the circulatory system, permitting distant cells to be affected e. None of the above 3. Which of the following chemical messengers pass through the plasma membrane of cells and have receptor molecules in the cytoplasm? a. Testosterone b. Insulin c. cAMP d. GTP e. Epinephrine 4. The source of phosphate for a phosphorylation cascade is ____________. a. cAMP b. protein kinase c. protein phosphatase d. ATP e. GDP 5. Which of the following is activated when the binding of signal molecules causes it to form a dimer? a. Ion-channel receptors b. G-protein receptors c. Protein kinase receptors d. Protein phosphatase receptors e. Adenylyl cyclase receptors 6. Which of the following statements is true? a. When a ligand binds a G-protein linked receptor, the G protein associated with the receptor is phosphorylated and becomes active b. Local regulators bind their receptors and are internalized by endocytosis, triggering the cell’s response. c. In most cases, signaling molecules never actually enter the cytoplasm, but interact only with proteins on the plasma membrane d. Increased cytoplasmic levels of second messengers cause calcium ions to move rapidly out of the cell e. Steroid hormone receptors have kinase activity
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7. A difference between the mechanisms of cAMP and calcium in signal transduction is that cAMP ____________ and calcium _______________. a. In synthesized by an enzyme in response to a signal; is released from cell compartments such as the ER b. Is always present at high levels in the cytosol; is present at low levels in the absence of a signal c. Is stored in the ER; is not stored in the cell d. Enters the cell via a transmembrane protein channel; is never stored in the cell e. Is the product of a protein kinase reaction; is linked to a G-protein receptor 8. Estrogen does not affect all cells of the body because ____________________. a.
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This note was uploaded on 11/17/2011 for the course BIO 12334343 taught by Professor Jony during the Fall '09 term at Arizona.

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Bio exam 4 2009 - 1 2 3 4 5 6 Biology 181R Exam#4 From the...

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