Final answer:
Cells with a high concentration of rough endoplasmic reticulum (RER) are typically involved in the synthesis and secretion of proteins, such as liver cells. The RER is responsible for protein folding, modification, and phospholipid synthesis, while SER focuses on lipid synthesis and other functions.
Step-by-step explanation:
Large amounts of rough endoplasmic reticulum (RER) are found in cells that are specialized in protein synthesis and secretion. Such cells include liver cells, which are well known for their capacity to produce and secrete proteins such as various plasma proteins and enzymes. The RER is involved in the initial phases of protein synthesis, where ribosomes are responsible for assembling amino acids into proteins. These proteins are destined for incorporation into cellular membranes, secretion out of the cell, or use within the cell.
The RER also modifies proteins through folding and the addition of side chains, while the smooth endoplasmic reticulum (SER), which lacks ribosomes, is involved in lipid and carbohydrate synthesis, detoxification, and calcium ion storage.