For each of the following sentences, select the best word or phrase from the lis

Question

For each of the following sentences, select the best word or phrase from the list below to fill in the blanks. Not all words or phrases will be used; each word or phrase should be used only once. An extracellular signal molecule can act to change a cell's behavior by acting through cell-surface __________________ that control intracellular signaling proteins. These intracellular signaling proteins ultimately change the activity of __________________ proteins that bring about cell responses. Intracellular signaling proteins can __________________ the signal received to evoke a strong response from just a few extracellular signal molecules. A cell that receives more than one extracellular signal at the same time can __________________ this information using intracellular signaling proteins. __________________ proteins can act as molecular switches, letting a cell know that a signal has been received. Enzymes that phosphorylate proteins, termed ___________, can also serve as molecular switches; the actions of these enzymes are countered by the activity of __________________. GMP-binding effector cleavage acetylase GTP-binding decrease decouple receptors protein phosphatases esterases sterols sutocrine neurotransmitter integrate convolute amplify AMP-binding protein kinases Name the three main classes of cell-surface receptor. Which of the following statements is true? Extracellular signal molecules that are hydrophilic must bind to a cell-surface receptor so as to signal a target cell to change its behavior. To function, all extracellular signal molecules must be transported by their receptor across the plasma membrane into the cytosol. A cell-surface receptor capable of binding only one type of signal molecule can mediate only one kind of cell response. Any foreign substance that binds to a receptor for a normal signal molecule will always induce the same response that is produced by that signal molecule on the same cell type. Which of the following statements about molecular switches is false? Phosphatases remove the phosphate from GTP on GTP-binding proteins, turning them off. Protein kinases transfer the terminal phosphate from ATP onto a protein Serine/threonine kinases are the most common types of protein kinase. A GTP-binding protein exchanges its bound GDP for GTP to become activated. G-Protein-Coupled Receptors For each of the following sentences, select the best word or phrase from the list below to fill in the blanks. Not all words or phrases will be used; each word or phrase should be used only once. G-protein-coupled receptors (GPCRs) all have a similar structure with _______________ transmembrane domains. When a GPCR binds an extracellular signal, an intracellular G protein, composed of ___________ subunits, becomes activated, ____________ of the G-protein subunits are tethered to the plasma membrane by short lipid tails. When unstimulated, the alpha subunit is bound to _____________, which is exchanged for _____________ on stimulation. The intrinsic ______________ activity of the alpha subunit is important for inactivating the G protein, ___________ inhibits this activity of the alpha subunit, thereby keeping the subunit in an active state.

Explanation / Answer

Answer:16-16:Receptor

Effector

Amplify

Integrate

GTP binding

Protein kinases

Protein phosphatases

Answer16-17:1.Ion-channel-coupled-receptors

2.G protein coupled receptors

3.Enzyme coupled receptors

Answer16-18:Choice A is correct because a hydrophillic molecule cannot diffuse across the membrane and it can only effect a cell if it binds to the cell surface receptor.

Answer16-19:Choice A is incorrect :GTP binding proteins themselves hydrolyze their bound GTP to GDP using their own intrinsic GTPase activity.

Answer16-22:1.Seven transmembrane domains

2. Three subunits-Alpha,Beta,Gamma

3.

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