Insulin formed by the Golgi apparatus in insulin-producing cells leaves those cells by
A) special pore molecules that are embedded in the cell membrane.
B) the insulin-filled vesicles fusing with the cell membrane and spilling their contents externally.
C) moving along the endoplasmic reticulum until it is outside the cell membrane.
D) the Golgi apparatus being connected with external channels directly to the cell membrane.
E) diffusion across the cytoplasm.

Question

Quizplus · Accepted Answer

Insulin is a large molecule that is secreted from the cells by exocytosis. There are no pores in a cell for secretion and the endoplasmic reticulum and Golgi apparatus are not connected to the outside of the cell. Insulin is too large a molecule to diffuse across a membrane.

Insulin Formed by the Golgi Apparatus in Insulin-Producing Cells Leaves