Multiple ChoiceKinases and phosphatases are essential to the cell because they:a) Are enzymes that synthesize proteins.b) Are enzymes that degrade proteins.c) Are enzymes that can turn proteins 'on' and/or 'off' through changes in phosphorylation.d) Are enzymes that can turn proteins 'on' and/or 'off' through changes in proton concentrations.e) None of the above.9841Has a video solution.
Multiple ChoiceWhat role do phosphatases play in signal transduction pathways?a) They phosphorylate proteins involved in signal transduction or cellular response.b) They activate protein kinases by phosphorylation.c) They amplify the signal molecule.d) They regulate the function of proteins involved in signal transduction pathways or cellular response.24032Has a video solution.
Multiple ChoicePhosphorylation cascades are useful signal transduction pathways because they ________.a) Allow proteins to be easily activated by adding or removing a phosphate group.b) Allow proteins to be easily deactivated by adding or removing a phosphate group.c) Amplify the original signal many times.d) All of the above.13951Has a video solution.
Multiple ChoiceIn liver cells, epinephrine stimulates the breakdown of glycogen. As the signal-transduction pathway progresses, __________. 178
Multiple ChoiceA mutation in the active site of adenylyl cyclase that inactivates it would most likely lead to __________. 300
Multiple ChoiceThe general name for an enzyme that transfers phosphate groups from ATP to a protein is __________. 326
Multiple ChoiceATPgammaS is a form of ATP that cannot be hydrolyzed by enzymes. If this compound were introduced to cells so that it replaced the normal ATP present in the cell, which of the following would you predict? 185
Multiple ChoiceSecond messengers tend to be water-soluble and small. This accounts for their ability to __________. 367
Multiple ChoiceDuring the transduction of a signal, one molecule or ion may be closely associated with the activity of another. Which of the following pairs correctly combines two associated molecules? 211
Multiple ChoiceIn eukaryotic cells, which of the following is a second messenger that is produced as a response to an external signal such as a hormone? 2241
Multiple ChoiceA difference between the mechanisms of cAMP and Ca2+ in signal transduction is that cAMP __________ and Ca2+ __________. 362
Textbook QuestionThe activation of receptor tyrosine kinases is characterized by a. dimerization and phosphorylation. b. dimerization and IP3 binding. c. a phosphorylation cascade. d. GTP hydrolysis.732Has a video solution.
Textbook QuestionConsider this pathway: epinephrine → G protein-coupled receptor → G protein → adenylyl cyclase → cAMP. Identify the second messenger. a. cAMP b. G protein c. GTP d. adenylyl cyclase929Has a video solution.
Textbook QuestionWhich observation suggested to Sutherland the involvement of a second messenger in epinephrine's effect on liver cells? a. Enzymatic activity was proportional to the amount of calcium added to a cell-free extract. b. Receptor studies indicated that epinephrine was a ligand. c. Glycogen breakdown was observed only when epinephrine was administered to intact cells. d. Glycogen breakdown was observed only when epinephrine and glycogen phosphorylase were mixed.479Has a video solution.
Textbook QuestionProtein phosphorylation is commonly involved with all of the following except a. activation of receptor tyrosine kinases. b. activation of protein kinase molecules. c. activation of G protein-coupled receptors. d. regulation of transcription by signaling molecules.974Has a video solution.
Textbook QuestionSuppose you were to model amplification by the phosphorylation cascade in Figure 11.16, using a penny for each kinase 1, a nickel for each kinase 2, and a dime for each kinase 3. Also suppose that Ras and each of the kinases can activate 10 proteins. How much money would you need to construct your model?146Has a video solution.
Textbook QuestionSuppose you were to model amplification by the phosphorylation cascade in Figure 11.16, using a penny for each kinase 1, a nickel for each kinase 2, and a dime for each kinase 3. Also suppose that Ras and each of the kinases can activate 10 proteins. How much money would you need to construct your model?127Has a video solution.
Textbook QuestionWhat is the significance of the observation that many signal transduction pathways create a network, where they intersect or overlap?190Has a video solution.
Textbook QuestionSteroid hormones, like most lipid-soluble signaling molecules, are processed directly. How does the absence of a signal transduction cascade in the processing of steroid hormones affect the cellular response that is possible?305Has a video solution.
Textbook QuestionSteroid hormones, like most lipid-soluble signaling molecules, are processed directly. How does the absence of a signal transduction cascade in the processing of steroid hormones affect (b) signal regulation?159Has a video solution.
Textbook QuestionSteroid hormones, like most lipid-soluble signaling molecules, are processed directly. How does the absence of a signal transduction cascade in the processing of steroid hormones affect (b) signal regulation?146Has a video solution.
Textbook QuestionSteroid hormones, like most lipid-soluble signaling molecules, are processed directly. How does the absence of a signal transduction cascade in the processing of steroid hormones affect (a) signal amplification?226Has a video solution.
