Hans Spemann and colleagues developed the concept of the "organizer" in amphibian embryos while studying the ________.

#Question id: 1201

#Unit 4. Cell Communication and Cell Signaling

Epinephrine binds to the same type of receptors in liver, fat, and smooth muscle cells. Yet in liver, glycogen breaks down; in fat, triacylglycerols break down; and smooth muscle cells relax. How can the same hormone produce three such different responses?

#Question id: 1202

#Unit 4. Cell Communication and Cell Signaling

G proteins are said to be self-inactivating. What G-protein function accounts for this?

#Question id: 1203

#Unit 4. Cell Communication and Cell Signaling

People who suffer from thyroid adenomas have constitutively activated G proteins in some cells of the thyroid gland. Tumor cells not only secrete copious quantities of thyroid hormones but also divide and grow excessively. Based on these observations, in what kind(s) of signal transduction pathways do the mutant G proteins participate?

#Question id: 1204

#Unit 4. Cell Communication and Cell Signaling

What factors are responsible for the specificity of G protein-coupled responses?

#Question id: 1205

#Unit 4. Cell Communication and Cell Signaling

Acetylcholine on a smooth muscle cell is to phospholipase C as epinephrine on a liver cell is to    ?    .

#Question id: 1206

#Unit 4. Cell Communication and Cell Signaling

Serine and threonine are to ........  as tyrosine is to receptor tyrosine kinases.