In regulation by repression Multiple Choice an amino acid activates the repressor so that the repressor binds to the operator an
d prevents transcription. an inducer activates the activator so that it binds to DNA and prevents transcription. an amino acid binds to the operator, blocking the repressor, allowing transcription to proceed. a sugar, such as lactose, acts as an inducer and combines with the repressor to prevent transcription. T/F
In molecular and genetic biology, a transcription factor (sometimes called a specific DNA sequence binding factor) is a protein that binds to specific DNA sequences, thus controlling the transcription of genetic information from DNA to messenger RNA. Transcription factors do this alone or in conjunction with other protein complexes by promoting (as an activator) or silencing (as a repressor) the recruitment of RNA polymerase (the enzyme that transcribes genetic information from DNA to RNA) to specific genes
A determining feature of transcription factors is that they contain one or more DNA-binding domains (DBDs), which bind to specific DNA sequences adjacent to the genes they regulate. Additional proteins such as coactivators, chromatin remodelers, histone acetyltransferases, deacetylases, kinases and methyltransferases, also play crucial roles in genetic regulation, but lack DBDs and, therefore, are not classified as transcription factors.
Ninhydrin causes prints to turn a purple color, which makes them easily photographed. DFO (1,2-diazafluoren-9-one) is another chemical used to locate latent fingerprints on porous surfaces; it causes fingerprints to fluoresce, or glow, when they are illuminated by blue-green light.
