Why are bacteria and yeast cells used to make large amounts of human protein?

Bacteria and yeast cells are used to produce large amounts of human proteins because they can be genetically engineered to express these proteins efficiently and cost-effectively. Their rapid growth rates allow for high yields in a short time, and they can be cultured in simple, controlled environments. Additionally, these microorganisms can perform post-translational modifications, which are essential for the proper functioning of many human proteins. This makes them valuable tools in biotechnology and pharmaceutical production.