Final answer:
Adult cells are typically unable to regenerate and become specialized through differentiation, where unspecialized stem cells develop into specific cell types. Stem cells play a vital role in replenishing short-lived cells like red blood cells.
Step-by-step explanation:
Most cells in the adult body are no longer capable of regenerating. These terminally differentiated cells, with few exceptions, do not divide again and have a finite lifespan, requiring periodic replacement by stem cells. Cells become specialized through the process of differentiation. During this process, cells undergo changes in size, shape, metabolic activity, and function. Despite all cells containing the same DNA, they only express certain genes relevant to their specific role, akin to actors only reading their part in a movie script. The transformation from unspecialized stem cells to distinct cell types is crucial for the development of complex organisms, enabling the formation of diverse tissues and organ systems.
Stem cells exist in several categories based on their potential to differentiate. They play a critical role in replenishing cells like red blood cells, which have a short lifespan. Stem cells' capability to divide indefinitely and differentiate under specific conditions is pivotal for the maintenance and repair of the body. The process of cell differentiation is governed by transcription factors that regulate gene expression, ultimately determining a cell's unique attributes.