What is a grain like structure that makes and store protein?

A grain-like structure that makes and stores protein is called a ribosome. Ribosomes are cellular organelles composed of ribosomal RNA (rRNA) and proteins, and they play a crucial role in translating messenger RNA (mRNA) into proteins. They can be found free in the cytoplasm or attached to the endoplasmic reticulum, contributing to protein synthesis within the cell.