What is the primary way growth factors stimulate animal cell growth?

Growth factors are signaling molecules that play a critical role in regulating various cellular processes, including growth, proliferation, and differentiation. The primary mechanism by which growth factors stimulate animal cell growth is by promoting protein synthesis.

When a growth factor binds to its corresponding receptor on the surface of a cell, it triggers a cascade of intracellular signaling pathways that lead to the activation of transcription factors. These transcription factors then promote the expression of genes involved in the synthesis of proteins that are necessary for cell growth and division. This protein synthesis is essential as it generates the structural proteins, enzymes, and other molecules required for new cell development, thereby facilitating cell growth and tissue formation.

While reducing apoptosis and enhancing DNA repair are relevant to cell survival and the maintenance of genomic integrity, they are secondary mechanisms that can support cell growth rather than directly stimulating it. Increasing cell cycle checkpoints does not promote growth but instead regulates the timing of cell division. In contrast, the stimulation of protein synthesis directly boosts the cellular machinery needed for growth and division in response to growth factor signals.