Campbell s Biology 9e Reece et al Chapter 11 Cell Communication Students will encounter the topic of cell signaling repeatedly in this course and throughout their studies of biology Therefore the more confident they are regarding the basic principles the more successful they are liable to be when encountering the topic This chapter includes more higher skill level questions and makes connections to the principle of evolution as well as to other chapters of the text Multiple Choice Questions 1 Using the yeast signal transduction pathways both types of mating cells release the mating factors These factors bind to specific receptors on the correct cells A which induce changes in the cells that lead to cell fusion B which produce more of the a factor in a positive feedback C then one cell nucleus binds the mating factors and produces a new nucleus in the opposite cell D stimulating cell membrane disintegration releasing the mating factors that lead to new yeast cells E which in turn releases a growth factor that stimulates mitosis in both cells Answer A Topic Concept 11 1 Skill Knowledge Comprehension 2 What is most likely to happen to an animal s target cells that lack receptors for local regulators A They might compensate by receiving nutrients via a factor B They could develop normally in response to neurotransmitters instead C They could divide but never reach full size D They might not be able to multiply in response to growth factors from nearby cells E Hormones would not be able to interact with target cells Answer D Topic Concept 11 1 Skill Application Analysis 3 Which of the following is a likely explanation of why natural selection favored the evolution of signals for sexual reproduction A Even in the simplest organisms sexual reproduction required several coordinated responses by cells B Multicellular eukaryotes required signals that were responded to by multiple organ systems C Cells of several kinds of mating types needed to sort themselves to allow self recognition D Rooted plants required chemical diffusible signals that could travel throughout the organism E Hormones required a mechanism for introducing changes in their target tissues Answer A Topic Concept 11 1 Skill Synthesis Evaluation 1 Copyright 2011 Pearson Education Inc 4 Which of the following is characterized by a cell releasing a signal molecule into the environment followed by a number of cells in the immediate vicinity responding A hormonal signaling B autocrine signaling C paracrine signaling D endocrine signaling E synaptic signaling Answer C Topic Concept 11 1 Skill Knowledge Comprehension 5 In the formation of biofilms such as those forming on unbrushed teeth cell signaling serves which function A formation of mating complexes B secretion of apoptotic signals C aggregation of bacteria that can cause cavities D secretion of substances that inhibit foreign bacteria E digestion of unwanted parasite populations Answer C Topic Concept 11 1 Skill Knowledge Comprehension 6 In yeast signal transduction the yeast cells A must physically and directly interact B produce signal molecules that change themselves so they can interact with one another C produce response molecules that diffuse to other yeast cells D secrete molecules that result in response by other yeast cells E mate after which the new cells secrete hybrid signals Answer D Topic Concept 11 1 Skill Knowledge Comprehension 7 In which of the following ways do plant hormones differ from hormones in animals A Plant hormones interact primarily with intracellular receptors B Plant hormones may travel in air or through vascular systems C Animal hormones are found in much greater concentration D Plant hormones are synthesized from two or more distinct molecules E Animal hormones are primarily for mating and embryonic development Answer B Topic Concept 11 1 Skill Knowledge Comprehension 2 Copyright 2011 Pearson Education Inc 8 In an experiment to track the movement of growth factor molecules from secretion to the point of receptor binding in a particular species of mammal a student found a 20 fold reduction in mm traveled when in the presence of an adrenal hormone This is in part attributable to which of the following A The growth factor is a paracrine signal B The growth factor depends on osmosis C The mammal only carries growth factor through the lymph D The growth factor is an exocrine signal E The growth factor is an endocrine signal Answer A Topic Concept 11 1 Skill Synthesis Evaluation 9 When a neuron responds to a particular neurotransmitter by opening gated ion channels the neurotransmitter is serving as which part of the signal pathway A receptor B relay molecule C transducer D signal molecule E endocrine molecule Answer D Topic Concept 11 1 Skill Application Analysis 10 Of the following a receptor protein in a membrane that recognizes a chemical signal is most similar to A the active site of an allosteric enzyme that binds to a specific substrate B tRNA specifying which amino acids are in a polypeptide C a metabolic pathway operating within a specific organelle D an enzyme having an optimum pH and temperature for activity E an antibody in the immune system Answer A Topic Concept 11 2 Skill Knowledge Comprehension 11 Which of the following is true for the signaling system in an animal cell that lacks the ability to produce GTP A It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane B It could activate only the epinephrine system C It would be able to carry out reception and transduction but would not be able to respond to a signal D It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane E It would employ a transduction pathway directly from an external messenger Answer A Topic Concept 11 2 Skill Application Analysis 3 Copyright 2011 Pearson Education Inc 12 Testosterone functions inside a cell by A acting as a signal receptor that activates tyrosine kinases B binding with a receptor protein that enters the nucleus and activates specific genes C acting as a steroid signal receptor that activates ion channel proteins D becoming a second messenger that inhibits adenylyl cyclase E coordinating a phosphorylation cascade that increases spermatogenesis Answer B Topic Concept 11 2 Skill Knowledge Comprehension 13 Which of the following is true of transcription factors A They regulate the synthesis of DNA in response to a signal B They