03:13Receptors and Second Messenger system; G-protein, Enzyme linked and Ligand gated ion channelsPharmacology Animation1161views
03:38G Protein Coupled Receptors(GPCRs) - Structure, Function, Mechanism of Action. Everything!Med Today1415views
Multiple ChoiceThe molecules that convert extracellular signals into intracellular signals are:1761views11rank1comments
Multiple ChoiceWhich type of receptor leads directly to a change in the distribution of ions on opposite sides of the membrane?1748views10rank1comments
Multiple ChoiceWhy does testosterone, a lipid-soluble / hydrophobic signaling molecule, not affect all cells in the body but only specific cells?2739views10rank
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? 1946views1rank
Multiple ChoiceSteroid hormones can enter a cell by simple diffusion. Therefore, steroids __________. 1083views
Multiple ChoiceG-protein-coupled receptors __________, whereas receptor tyrosine kinases __________. 1266views2rank
Multiple ChoiceWhich of the following is activated when the binding of single molecules causes it to form a dimer? 735views
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? 696views1rank
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 __________. 720views1rank
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? 1408views1rank
Textbook QuestionLipid-soluble signaling molecules, such as aldosterone, cross the membranes of all cells but affect only target cells because a. only target cells retain the appropriate DNA segments. b. intracellular receptors are present only in target cells. c. only target cells have enzymes that break down aldosterone. d. only in target cells is aldosterone able to initiate the phosphorylation cascade that turns genes on.1420views
Textbook QuestionSummarize the experimental evidence in sponges showing that animal cells adhere to each other selectively. Explain the molecular basis of selective adhesion.624views
Textbook QuestionSuppose you have an antibody that binds to the receptor tyrosine kinase illustrated in Figure 11.16. When you add this antibody to the cell, you find that it activates the cell response, even when no signaling molecule is present. Explain this result.495views
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