Exam 9: Cellular Signaling

Binding of epinephrine to its receptor results in which of the following events?

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?

Which of the following statements best describes the mechanism by which testosterone functions inside a cell?

A loss of function of Apaf1, the human homologue of ced-4 in nematodes, is most likely to result in which of the following?

Which of the following statements best describes the effect of a mutation that knocks out the GTPase activity of a G protein?

Which of the following signal transduction proteins typically functions by forming dimers after binding to a signal molecule?

Which of the following responses is stimulated by cell signaling the formation of biofilms?

What role do phosphatases play in signal transduction pathways?

Some cases of human melanoma have been shown to result from inhibition of apoptosis in these cells. The human analogue of which of the following defects in C. elegans could cause these cancers?

Which of the following statements best describes the function of the α factor secreted by yeast cells?

Viagra causes dilation of blood vessels and increased blood flow to the penis, which helps to maintain an erection. Viagra acts by inhibiting which of the following events?

Which of the following statements best describes the mechanism by which the ced-9 protein in the nematode C. elegans prevents apoptosis in normal cells?

Which of the following conditions is required for a target organ to respond to a particular hormone?

Not all intercellular signals require transduction. Which one of the following signals may be processed without transduction?

Many G protein-coupled receptors contain seven transmembrane α-helical domains. If the amino terminus of such a protein is located on the extracellular side of the membrane, where would you expect to find the carboxyl terminus of the protein?

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

Lipid-soluble signaling molecules, such as aldosterone, cross the membranes of all cells but affect only target cells because ________.

Caffeine is an inhibitor of phosphodiesterase. Therefore, the cells of a person who has recently consumed coffee would have increased levels of which of the following molecules?

Which of the following amino acids are most frequently phosphorylated by protein kinases in the cytosol during signal transduction?

Many G protein-coupled receptors contain seven transmembrane α-helical domains. If the amino terminus of such a protein is located on the extracellular side of the membrane, where would a coupled G protein most likely interact with this receptor?