Question

1.a) Which of the following is/are examples of cell-cell attachment mechanisms?

Select all that apply. Select one or more: a. G proteins b. Desmosomes c. Tight junctions d. Gap junctions

b) A G-protein is "active" when which of the following are bound to it?

Select one: a. GDP b. ADP c. ATP d. GTP

Answer 1

1 a) The answer is option A, B, C, and D

The tight junction is the cell-cell attachment in which the plasma cells of both cells fuse together to form a tight junction. So option C is correct.

The gap junction is the junction between adjacent epithelial cells for the exchange of chemicals between the two. Thus option D is also correct.

The desmosomes are one of the types of adhering junction where cells are attached to each other by a cementing function. Thus option B is also correct.

The G-proteins are the integral proteins that are attached to the epithelium by the tight junction. Thus option A is also correct.

b)The answer is option D.

The activation of the G proteins is indicated by the binding of it to the GTP and deactivation by binding to the GDP whereas ATP and ADP have no role G protein activation but the Gs cause the production of ATP from cAMP. Thus the answer is option D.