Final answer:
a. Necrosis
The process where living cells are converted to dead protein cells is called necrosis if it occurs accidentally through external injury, or apoptosis if it is a regulated, programmed cell death. Autolysis is the self-degradation of cells, and denaturation is a structural change in proteins that does not affect their primary structure.
Step-by-step explanation:
The conversion of living cells into dead protein cells can be described by the process of necrosis or apoptosis. Necrosis is when cells die from external injury and undergo an accidental, uncontrolled death. In contrast, apoptosis is a form of programmed cell death that occurs in a regulated manner and is a normal part of development and cellular turnover. It involves molecular events leading to cell death, such as the release of cytochrome C from the mitochondria prompted by signals to the Bcl2 proteins Bak and Bax, and the activation of caspases which are proteolytic enzymes that digest cellular proteins. Unlike necrosis, apoptosis does not cause inflammation and the cellular debris is often recycled by the body. Autolysis is the self-digestion of cells by their own enzymes, while denaturation refers to the loss of the secondary, tertiary, and quaternary structures of proteins due to physical or chemical agents, without affecting the primary structure.