Hydrolysis of gtp to gdp by a gtpase can cause a change in which aspect(s) of that protein's structure?
a. primary structure.
b. tertiary structure.
c. both of the above.
d. neither of the above.

Tertiary structure.

Explanation:

The G protein coupled receptor gets activated and deactivated whether they bound to GTP to GDP. This coupling is important for the initiation of signalling cascades in the cells.

The hydrolysis of GTP to GDP is carried out by the enzyme GTPase. This causes the change in the tertiary structure of protein. The different subunits of G protein gets change due to the hydrolysis. This changes the tertiary structure of the protein and any change in the primary structure of protein is not reversible.

Thus, the correct answer is option (b).