Final answer:
Transcription factors are proteins that regulate gene expression by binding to specific DNA sequences to activate or repress gene transcription, influencing stem cell differentiation.
Step-by-step explanation:
The statement that describes the role of transcription factors in the process of stem cell differentiation is: b) Transcription factors are proteins that can turn on (activate) or turn off (repress) certain genes in the stem cell. Transcription factors play a critical role in gene expression and are essential for a stem cell to develop into its specialized form and function. These proteins bind to specific genes on the DNA molecule and either promote or inhibit their transcription. By doing so, transcription factors control which proteins are produced by the cell, guiding the cell through the differentiation process.
In addition to general transcription factors, there are transcription factors that bind specifically to a particular DNA sequence motif on the promoter of a gene. This action influences the binding of RNA polymerase to the gene, thus regulating transcription. Transcription factors act as activators or repressors, either enhancing or suppressing gene transcription in response to environmental stimuli.