Which of the following molecules is notan integral membrane protein? a. the insulin receptorb. the epinephrine receptorc. the ryanodine channeld. the glucocorticoid receptore. the growth factor receptor

Option D.

Explanation:

An integral membrane protein is a type of membrane protein that is permanently attached to the biological membrane, including transmembrane proteins. Insulin receptor, epinephrine receptor, growth factor receptor and ryanodine channel are receptors/ channels which implies its presence on the cell membrane for signal from binding ligand to be translocated into the cell through a signalling cascade. Glucocorticoid is an lipophilic signalling molecule which can pass through the cell surface membrane (due to its lipophilic characteristic that enables it to pass through the hydrophobic core of the phospholipid bilayer) and acts on its receptor in the cell cytosol. Hence the glucocorticoid receptor is not on the cell surface membrane and is thus not an integral membrane protein.