The pathway for polypeptides exported from E. coli includes the following steps, which occur in what order for correct export?

1.  A chaperone, SecA, binds to the polypeptide.

2.  A chaperone, SecB, binds to the polypeptide.

3.  ATP is hydrolyzed by Sec A.

4.  SecA pushes 20 amino acids of the polypeptide into the translocation complex.

#Question id: 1085

#Unit 4. Cell Communication and Cell Signaling

Which of the following statements about a G protein signaling pathway is true?

#Question id: 1086

#Unit 4. Cell Communication and Cell Signaling

What is the most likely mechanism by which testosterone functions inside a cell?

#Question id: 1087

#Unit 4. Cell Communication and Cell Signaling

Scientists have found that extracellular matrix components may induce specific gene expression in embryonic tissues such as the liver and testes. For this to happen, there must be direct communication between the extracellular matrix and the developing cells. Which kind of transmembrane protein would most likely be involved in this kind of induction?

#Question id: 1088

#Unit 4. Cell Communication and Cell Signaling

One of the major categories of receptors in the plasma membrane functions by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this?

#Question id: 1089

#Unit 4. Cell Communication and Cell Signaling

Which of the following statements describes a likely effect of a drug designed that inhibits the cellular response to testosterone?

#Question id: 1090

#Unit 4. Cell Communication and Cell Signaling

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?