Question

Long flattened, usually unbranched units arranged in parallel stacks in endoplasmic reticulum are called

• A. cisternae
• B. cristae
• C. vesicles
• D. tubules

Answer 1

The correct option is A

cisternae

Cisternae are the flattened usually unbranched, sac-like units of the endoplasmic reticulum. These are arranged in stacks or piles parallel to one another and bear ribosomes.
Tubules are tubular branched elements of ER, vesicles are oval or rounded, vacuole-like elements of ER scattered in the cytoplasm, while cristae are the infoldings of the inner membrane of mitochondria.