The stomach has two types of exocrine secretory cells:

• chief cells that secrete an inactive form of a protein-digesting enzyme, pepsinogen
• parietal cells that secrete hydrochloric acid (HCl), which activates pepsinogen

Both these cell types have an abundance of mitochondria for ATP production – the chief cells for the energy needed needed to synthesize pepsinogen, the parietal cells for the energy needed to transport H⁺ and Cl^– from the blood into the stomach lumen. But only one of these cell types also has an extensive rough endoplasmic reticulum and abundant Golgi stacks.

Explain which cell type would have extensive rough ER  and Golgi stacks and why.

Also explain which cell type would not have as extensive a rough ER and Golgi stacks and why.