03:13Receptors and Second Messenger system; G-protein, Enzyme linked and Ligand gated ion channelsPharmacology Animation924views
03:38G Protein Coupled Receptors(GPCRs) - Structure, Function, Mechanism of Action. Everything!Med Today1149views
Multiple ChoiceThe molecules that convert extracellular signals into intracellular signals are:a) Neurotransmitters.b) Hormones.c) Cell surface receptors.d) Intracellular receptors.1498views9rank1comments
Multiple ChoiceWhich type of receptor leads directly to a change in the distribution of ions on opposite sides of the membrane?a) Receptor tyrosine kinase.b) G protein-coupled receptor.c) Ligand-gated ion channel.d) Steroid receptor.e) Intracellular receptor.1530views6rank1comments
Multiple ChoiceWhy does testosterone, a lipid-soluble / hydrophobic signaling molecule, not affect all cells in the body but only specific cells?a) Only target cells have the cell surface receptor able to bind with testosterone.b) Only target cells contain the genes regulated by testosterone.c) Only target cells possess the phosphorylation cascade uniquely activated by testosterone.d) Only target cells possess the intracellular receptor able to bind with testosterone.2366views8rank
Multiple ChoiceTestosterone and estrogen are lipid-soluble signal molecules that cross the plasma membrane by simple diffusion. If these molecules can enter all cells, why do only specific cells respond to their presence? 1688views
Multiple ChoiceSteroid hormones can enter a cell by simple diffusion. Therefore, steroids __________. 822views
Multiple ChoiceG-protein-coupled receptors __________, whereas receptor tyrosine kinases __________. 1013views2rank
Multiple ChoiceWhich of the following is activated when the binding of single molecules causes it to form a dimer? 564views
Multiple ChoiceDomoic acid is a neurotoxin produced by some species of alga. Domoic acid binds to the kainate receptor on neurons in parts of the brain. The kainate receptor facilitates the movement of calcium into the cell. Excess domoic acid–induced stimulation of the neural kainate receptors causes neural damage and short-term memory loss. Based on this, which of the following is likely true? 535views
Multiple ChoiceIf a modified form of GTP that cannot be enzymatically converted to GDP were added to a culture of cells, the likely result would be __________. 563views1rank
Multiple ChoiceRas, a small G protein located at the plasma membrane, is often mutated in different types of cancer. Ras normally signals to a cell that it should divide. Cancer cells divide uncontrollably. Which of the following changes to Ras could explain uncontrolled division in a cancer cell that has mutated Ras present? 1157views1rank
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