BIOLOGY: Campbell's, Chapter 10: Cell Communication

Thyroid hormones bind to _____ receptors. intracellular G-protein-linked tyrosine-kinase plasma membrane ion-channel steroid

intracellular

Consider this pathway: epinephrine → G protein-coupled receptor → protein → adenylyl cyclase → cAMP. Identify the second messenger. GTP G protein cAMP adenylyl cyclase G protein-coupled receptor

cAMP

Histamine is a chemical substance released in inflammatory and allergic responses. The histamine H1 receptor on target cells is a G protein-coupled receptor that activates phospholipase C in response to the binding of histamine. Which statements are true about the binding of histamine to the histamine H1 receptor? Select all that apply. Histamine diffuses across the plasma membrane to bind to the H1 receptor. Histamine binds extracellularly to the H1 receptor. When histamine binds to the H1 receptor, the receptor undergoes a conformation change and binds the inactive G protein. Histamine binds intracellularly to the inactive G protein, activating the G protein. Once the G protein is active, it binds to the enzyme phospholipase C, activating it. Histamine is likely hydrophilic.

histamine binds extracellulary to the H1 receptor when histamine binds to the H1 receptor, the receptor undergoes a conformation change and binds the inactive G protein once the G protein is active, it binds the enzyme phospholipase C, activating it histamine is likely hydrophilic

Which of these is a logical signal transduction pathway? A receptor tyrosine kinase activates adenylyl cyclase, which activates phospholipase C, which converts ATP into cyclic AMP, which binds to an intracellular enzyme that carries out a response. An intracellular receptor activates phospholipase C, which cleaves a membrane protein to form IP3, which then activates the opening of an ER channel protein, which releases cyclic AMP into the cytoplasm, where it binds to an intracellular enzyme that carries out a response. A G-protein-linked receptor activates G protein, which activates phospholipase C, which cleaves a membrane lipid to form IP3, which binds to a calcium channel on the ER, which opens to release calcium ions into the cytoplasm, which bind to an intracellular enzyme that carries out a response. An ion-channel receptor opens, allowing a steroid hormone to enter the cell; the steroid hormone then activates protein kinases that convert GTP to GDP, which binds to an intracellular enzyme that carries out a response.

A G-protein-linked receptor activates G protein, which activates phospholipase C, which cleaves a membrane lipid to form IP3, which binds to a calcium channel on the ER, which opens to release calcium ions into the cytoplasm, which bind to an intracellular enzyme that carries out a response.

G-PROTEIN COUPLED RECEPTOR RECEPTOR TYROSINE KINASES BOTH NEITHER binding site for signaling molecule is located on the extracellular side of the cell interact directly with G protein catalyzes the transfer of a phosphate group to the receptor binding of the signaling molecule forms a dimer binding of the signaling molecule allows ions to flow through a channel in the receptor receptor is located in the plasma membrane

G PROTEIN COUPLED RECEPTORS interact directly with G proteins RECEPTOR TYROSINE KINASES binding of the signaling molecule forms a dimer catalyzes the transfer of phosphate group to the receptor BOTH receptor is located in the plasma membrane binding site for signaling molecule is located on the extracellular side of the cell NEITHER binding of the signaling molecule allows ions to flow through a channel in the receptor

A toxin that inhibits the production of GTP would interfere with the function of a signal transduction pathway that is initiated by the binding of a signal molecule to _____ receptors. ion-channel steroid intracellular G-protein-linked receptor tyrosine kinase

G-protein-linked

Epinephrine acts as a signal molecule that attaches to _____ proteins. G-protein-linked receptor nuclear receptor ion-channel receptor receptor tyrosine kinase intracellular receptor

G-protein-linked receptor

Which statement correctly distinguishes the roles of protein kinases and protein phosphatases in signal transduction pathways? Protein kinases activate enzymes by phosphorylating or adding phosphate groups to them. Protein phosphatases dephosphorylate or remove phosphate groups from enzymes, including protein kinases. Protein kinases are more critical than protein phosphatases to signal transduction enzymes. Protein kinases are involved in signal transduction in unicellular eukaryotes such as yeast. Protein phosphatases are involved in signal transduction in multicellular eukaryotes.

Protein kinases activate enzymes by phosphorylating or adding phosphate groups to them. Protein phosphatases dephosphorylate or remove phosphate groups from enzymes, including protein kinases.

RECEPTION TRANSDUCTION RESPONSE protein synthesis cAMP G protein coupled receptor signaling molecule adenylyl cylase IP3 receptor tyrosine kinase phosphorylation cascade second messenger Ca2+

RECEPTION signaling molecule G protein-coupled receptor receptor tyrosine kinase TRANSDUCTION adenylyl cyclase second messenger phosphorylation cascade cAMP IP3 Ca2+ RESPONSE protein synthesis

What are the functions of signal transduction pathways? Select all that apply. Signal transduction pathways amplify the effect of a signal molecule. 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. 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.

Select the statement that correctly distinguishes between relay proteins and second messengers in signal transduction pathways. Signal transduction pathways are multistep pathways that include relay proteins and small, nonprotein, water-soluble molecules or ions called second messengers. Relay proteins are the "first messengers," the extracellular signaling molecules that bind to the membrane receptor. The signal transduction pathways are then formed by the second messengers, which are the relay molecules that respond to the first messengers. Signal transduction pathways are multistep pathways in which relay proteins and second messengers alternate.

Signal transduction pathways are multistep pathways that include relay proteins and small, nonprotein, water-soluble molecules or ions called second messengers

Cyclic GMP, or cGMP, acts as a signaling molecule whose effects include relaxation of smooth muscle cells in artery walls. In the penis, this signaling pathway and the resulting dilation of blood vessels leads to an erection. Select the correct statement about the effect of Viagra on this signaling pathway. Viagra inhibits the hydrolysis of cGMP to GMP. Viagra increases the rate of hydrolysis of cGMP to GMP. Viagra prevents the formation of cGMP.

Viagra inhibits the hydrolysis of cGMP to GMP

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

activation of G protein-coupled receptors

A protein kinase activating many other protein kinases is an example of _____. mutualism a cellular response amplification deactivation sensitization

amplification

What role does a transcription factor play in a signal transduction pathway? By binding to a plasma membrane receptor it initiates a cascade. It relays a signal from the cytoplasm to the plasma membrane. It activates relay proteins. By binding to DNA it triggers the transcription of a specific gene. It is a plasma membrane protein that binds signal molecules.

by binding to DNA it triggers the transcription of a specific gene

Complete flowchart describing the interaction of cortisol with inctracellular receptors. cortisol-receptor complex enters the nucleus where it binds to genes. the transcribed mRNA is translated into aspecific protein. cortisol passes through the plasma membrane into the cytoplasm. cortisol-receptor complex forms in the cytoplasm cortisol-receptor acts as a transcription factor.

cortisol passes through the plasma membrane into the cytoplasm cortisol-receptor complex forms in the cytoplasm cortisol-receptor complex enters the nucleus where it binds to genes cortisol-receptor complex acts as a transcription factor the transcribed mRNA is translated into a specific protein

Which of these is NOT correct? Tyrosine-kinase receptors consist of two polypeptides that join when activated by a signal molecule. Ion channels are found on both the plasma membrane and the endoplasmic reticulum. Cyclic AMP binds to G-proteins. Kinases are enzymes that phosphorylate other molecules. Phospholipase C catalyzes the formation of IP3.

cyclic AMP binds to G-proteins

Which of these acts as a second messenger? cyclic AMP G-protein-linked receptor adenylyl kinase G protein protein kinase

cyclic MAP

The activation of receptor tyrosine kinases is characterized by a phosphorylation cascade. dimerization and phosphorylation. dimerization and IP3 binding. channel protein shape change. GTP hydrolysis.

dimerization and phosphorylation

Calcium ions that act as second messengers are stored in _____. mitochondria lysosomes endoplasmic reticula chloroplasts peroxisomes

endoplasmic reticula

Complete the flowchart showing the process of histamine signal transduction from the H1 receptor. calcium ions flow through the ligand-gated ion channel calcium ions activate a protein, leading to a cellular response enzyme clease PIP2, forming DAG adn IP3 calcium ion concentration increases in the cytosol IP3 binds to a ligand-gated ion channel in the ER membrane

enzyme cleaves PIP3 forming DAG and IP3 IP2 binds to a ligand gated ion channel in the ER membrane calcium ions flow through the ligand-gated ion channel calcium ion concentration inceases the cytosol calcium ions activate a protein, leading to a cellular response

Which of these extracellular signal molecules could diffuse through a plasma membrane and bind to an intracellular receptor? glycerol cellulose glucose estrogen starch

estrogen

The cleavage of glycogen by glycogen phosphorylase releases _____. fructose-1-phosphate cellulose glucose-1-phosphate nothing: glycogen phosphorylase cannot cleave glycogen galactose-1-phosphate

glucose-1-phosphate

Which observation suggested to Sutherland the involvement of a second messenger in epinephrine's effect on liver cells? Glycogen breakdown was observed when epinephrine and glycogen phosphorylase were combined. Glycogen breakdown was observed only when epinephrine was administered to intact cells. Receptor studies indicated that epinephrine was a ligand. Enzymatic activity was proportional to the amount of calcium added to a cell-free extract. Epinephrine was known to have different effects on different types of cells.

glycogen breakdown was observed only when ephinephrine was administered to intact cells

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

intracellular receptors are present only in target cells

A signal molecule is also known as a(n) _____. protein receptor initiator ligand key

ligand

Binding of a signaling molecule to which type of receptor leads directly to a change in the distribution of ions on opposite sides of the membrane? G protein-coupled receptor phosphorylated receptor tyrosine kinase dimer intracellular receptor receptor tyrosine kinase ligand-gated ion channel

ligand-gated ion channel

_____ catalyzes the production of _____, which then opens an ion channel that releases _____ into the cell's cytoplasm. Adenylyl cyclase ... cyclic AMP ... Ca2+ Protein kinase ... PIP2 ... Na+ Phospholipase C ... cyclic AMP ... Ca2+ Phospholipase C ... IP3 .... Ca2+ Adenylyl cyclase ... IP3 .... Ca2+

phospholipase C...IP3...Ca+2

A signal transduction pathway is initiated when a _____ binds to a receptor. G protein tyrosine kinase calmodulin signal molecule cyclic AMP

signal molecule

A(n) _____ is an example of a signal molecule that can bind to an intracellular receptor and thereby cause a gene to be turned on or off. carbohydrate ion steroid protein nucleic acid

steroid

The cholera bacterium Vibrio cholerae produces an enzyme toxin that chemically modifies a G protein involved in regulating salt and water secretion in intestinal cells. Stuck in its active form, the modified G protein stimulates the production of a high concentration of cAMP, which causes the intestinal cells to secrete large amounts of salts into the intestines, with water following by osmosis. An infected person quickly develops profuse diarrhea and if left untreated can soon die from the loss of water and salts. What is the basic effect of the cholera toxin? The basic effect of the cholera toxin is loss of specificity of the response of intestinal cells to a signaling molecule. The basic effect of the cholera toxin is premature termination of a signaling pathway. The basic effect of the cholera toxin is signal amplification.

the basic effect of the cholera toxin is signal amplification

Which of the following could account for the different cellular responses to histamine? Select all that apply. the type of second messengers involved in the signal transduction pathway the enzyme that is activated by the G protein associated with the receptor the types of relay molecules within the cell the cell type in which the histamine receptor is located the type of signaling molecule

the type of second messengers involved in the signal transduction pathway the enzyme that is activated by the G protein associated with the receptor the types of relay molecules within the cell the cell type in which the histamine receptor is located

Which of these is the second of the three stages of cell signaling? gene activation reception binding of a neurotransmitter to a plasma membrane receptor transduction cell response

transduction