<p>AP Biology Vocabulary & Roots: Ch. 11</p><p>1. adenylyl cyclase-An enzyme that converts ATP to cyclic AMP in response to a signal. 2. amplification-The strengthening of stimulus energy during transduction. 3. apoptosis-A program of controlled cell suicide, which is brought about by signals that trigger the activation of a cascade of suicide proteins in the cell destined to die. 4. biofilm-A surface-coating colony of one or more species of prokaryotes that engage in metabolic cooperation. 5. cyclic AMP (cAMP)-Cyclic adenosine monophosphate, a ring-shaped molecule made from ATP that is a common intracellular signaling molecule (second messenger) in eukaryotic cells. It is also a regulator of some bacterial operons. 6. cytoplasm-The contents of the cell, exclusive of the nucleus and bounded by the plasma membrane. 7. diacylglycerol (DAG)-A second messenger produced by the cleavage of a certain kind of phospholipid in the plasma membrane. 8. epinephrine-A catecholamine that, when secreted as a hormone by the adrenal medulla, mediates “fight-or-flight” responses to short-term stresses; also released by some neurons as a neurotransmitter; also known as adrenaline. 9. G protein- A GTP-binding protein that relays signals from a plasma membrane signal receptor, known as a G protein-coupled receptor, to other signal transduction proteins inside the cell. 10. gap junction-A type of intercellular junction in animals that allows the passage of materials between cells. 11. glycogen-An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch. 12. growth factor-(1) A protein that must be present in the extracellular environment (culture medium or animal body) for the growth and normal development of certain types of cells. (2) A local regulator that acts on nearby cells to stimulate cell proliferation and differentiation. 13. inositol trisphosphate (IP3)-A second messenger that functions as an intermediate between certain nonsteroid hormones and a third messenger, a rise in cytoplasmic Ca2+ concentration. 14. ligand-A molecule that binds specifically to another molecule, usually a larger one. 15. ligand-gated ion channel-A protein pore in cellular membranes that opens or closes in response to A signaling chemical (its ligand), allowing or blocking the flow of specific ions. 16. local regulator-A secreted molecule that influences cells near where it is secreted. 17. nitric oxide (NO)-A gas produced by many types of cells that functions as a local regulator and as a neurotransmitter. 18. protein kinase-An enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein. 19. protein phosphatase-An enzyme that removes phosphate groups from (dephosphorylates) proteins, often functioning to reverse the effect of a protein kinase. 20. receptor tyrosine kinase-A receptor protein in the plasma membrane, the cytoplasmic (intracellular) part of which can catalyze the transfer of a phosphate group from ATP to a tyrosine on another protein. Receptor tyrosine kinases often respond to the binding of a signaling molecule by dimerizing and then phosphorylating a tyrosine on the cytoplasmic portion of the other receptor in the dimer. The phosphorylated tyrosines on the receptors then activate other signal transduction proteins within the cell. 21. scaffolding protein-A type of large relay protein to which several other relay proteins are simultaneously attached, increasing the efficiency of signal transduction.</p><p>1 22. second messenger-A small, nonprotein, water-soluble molecule or ion, such as a calcium ion (Ca2+) or cyclic AMP, that relays a signal to a cell’s interior in response to a signaling molecule bound by a signal receptor protein. 23. signal transduction-The linkage of a mechanical, chemical, or electromagnetic stimulus to a specific cellular response. 24. signal transduction pathway-A series of steps linking a mechanical or chemical stimulus to a specific cellular response. 25. testosterone-A steroid hormone required for development of the male reproductive system, spermatogenesis, and male secondary sex characteristics; the major androgen in mammals. 26. transcription factor-A regulatory protein that binds to DNA and affects transcription of specific genes. 27. transduction- (2) In cellular communication, the conversion of a signal from outside the cell to a form that can bring about a specific cellular response. 28. yeast-Single-celled fungus that reproduces asexually by binary fission or by the pinching of small buds off a parent cell; some species exhibit cell fusion between different mating types.</p><p>Word Roots liga- = bound or tied (ligand: a small molecule that specifically binds to a larger one) trans- = across (signal transduction pathway: the process by which a signal on a cell's surface is converted into a specific cellular response inside the cell)</p><p>-yl = substance or matter (adenylyl cyclase: an enzyme built into the plasma membrane that converts ATP to cAMP)</p><p>2</p>