Question: Vitamin B12 is essential for the proper functioning of which type of cells? Need Assignment Help? Group of answer choices epithelial (skin) nerve hepatic (liver) gastric (stomach) Flag question: Question compound called TPP activates an enzyme critical in carbohydrate metabolism. TPP is Group of answer choices a B-vitamin called thiamin. a coenzyme. a derivative of adenosine triphosphate (ATP). a branched-chain amino acid.