Question

The endoplasmic reticulum is composed of flattened sacs called ________.

1) thylakoids.
2) cristae.
3) cisternae.
4) vacuomes.

Answer 1

The endoplasmic reticulum is composed of cisternae, which are flattened sacs. It is a network of phospholipid membranes that form hollow tubes, flattened sheets, and round sacs. The ER has two major functions: modifying proteins and synthesizing lipids.

Step-by-step explanation:

The endoplasmic reticulum (ER) is composed of cisternae, which are flattened sacs. These cisternae are a network of phospholipid membranes that form hollow tubes, flattened sheets, and round sacs. The ER has two major functions: modifying proteins and synthesizing lipids.