That "sarcoplasmic" (sar-co-PLAZZ-mic) type of this organelle is in turn a subset of a type of this structure which is the location of carbohydrate and steroid metabolism.
The sequence KDEL marks proteins for retention in this structure. Chaperone proteins located in this structure fold newly created proteins. A specialized variety of this structure stores calcium ions and is found in smooth and striated muscle. That "sarcoplasmic" (sar-co-PLAZZ-mic) type of this organelle is in turn a subset of a type of this structure which is the location of carbohydrate and steroid metabolism. That type is known as "transitional" or "smooth." For 10 points, name this organelle, which also has a "rough" type that contains ribosomes (RYE-bo-soams).
The sequence KDEL marks proteins for retention in this structure.
{endoplasmic reticulum} [or {ER}; or {smooth endoplasmic reticulum}; or {rough endoplasmic}