Chapter 8: Cell Communication – Flashcards

Which of the following is a type of local signaling in which a cell secretes a signal molecule that affects neighboring cells? autocrine signaling hormonal signaling paracrine signaling synaptic signaling

When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway? response molecule transducer relay molecule signal molecule

question 3

-soluble signaling molecules, such as testosterone, cross the membranes of all cells but affect only target cells because _____. only in target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor only target cells retain the appropriate DNA segments intracellular receptors are present only in target cells only target cells possess the cytosolic enzymes that transduce the testosterone SubmitMy AnswersGive Up Correct

Which of the following is true of steroid receptors? Steroid receptors are typically bound to the external surface of the nuclear membrane. The receptor may be inside the nucleus of a target cell. The receptor molecules are themselves lipids or glycolipids. The unbound steroid receptors are quickly recycled by lysosomes.

Which of the following is characteristic of a steroid hormone action? internal receptor binding cell-surface receptor binding second messenger activation protein phosphorylation

Which of the following sequences is correct? binding of a signaling molecule to its receptor → G protein activation → phospholipase C activation → IP3 production → increase in cytoplasmic calcium concentration binding of a growth factor to its receptor → phosphorylation cascade → activation of transcription factor → transcription diffusion of a signaling molecule across the plasma membrane → binding of the signaling molecule to its receptor → movement of the signaling molecule-receptor complex into the nucleus → transcription binding of a signaling molecule to its receptor → G protein activation → adenylyl cyclase activation → cAMP production → protein phosphorylation All of the choices are correct.

Adenylyl cyclase has the opposite effect of which of the following? phosphorylase phosphodiesterase protein kinase protein phosphatase

Which of the following is a correct association? adenylyl cyclase activity and the conversion of cAMP to AMP GTPase activity and hydrolysis of GTP to GDP phosphodiesterase activity and the removal of phosphate groups kinase activity and the addition of a tyrosine

In signal transduction, phosphatases _____. amplify the second messengers such as cAMP move the phosphate group of the transduction pathway to the next molecule of a series inactivate protein kinases and turn off the signal transduction prevent a protein kinase from being reused when there is another extracellular signal

question 11

Scaffolding proteins are _____. proteins that can reach into the nucleus of a cell to affect transcription microtubular protein arrays that allow lipid-soluble hormones to get from the cell membrane to the nuclear pores large molecules to which several relay proteins attach to facilitate cascade effects relay proteins that orient receptors and their ligands in appropriate directions to facilitate their complexing

Protein phosphorylation is commonly involved with all of the following except activation of G protein-coupled receptors. activation of protein kinase molecules. regulation of transcription by extracellular signaling molecules. activation of receptor tyrosine kinases. enzyme activation.

A What are the functions of signal transduction pathways? Select all that apply. Signal transduction pathways allow different types of cells to respond differently to the same signal molecule. Signal transduction pathways convert a signal on a cell's surface to a specific cellular response. Signal transduction pathways amplify the effect of a signal molecule.