The other object is a small charged sphere that is free to move (we neglect the force of. gravity on this sphere). According to Coulombâs law, these two like charges repel each. another. That is, the small sphere experiences a repulsive force away from the van de. Graaff sphere. Figure 2.2.2 (a) Two charges of the same sign that repel one another because of the. âstressesâ transmitted by electric fields.
Transcription is the first step of gene expression, in which a particular segment of DNA is copied into RNA (mRNA) by the enzyme RNA polymerase.
Transcription factor, molecule that controls the activity of a gene by determining whether the geneâs DNA (deoxyribonucleic acid) is transcribed into RNA (ribonucleic acid). The enzyme RNA polymerase catalyzes the chemical reactions that synthesize RNA, using the geneâs DNA as a template. Transcription factors control when, where, and how efficiently RNA polymerases function.