In eukaryotic cells, the option that directly regulates gene expression is "transcription factors."
Transcription factors are proteins that bind to specific DNA sequences called enhancers or promoters, located in the regulatory regions of genes. By binding to these DNA sequences, transcription factors can either activate or repress the transcription (synthesis) of RNA from the corresponding gene.
Transcription factors play a crucial role in regulating gene expression by controlling the initiation of transcription, a process where RNA polymerase binds to the DNA and begins synthesizing RNA. They can influence the recruitment of RNA polymerase to the gene promoter, modulate the rate of transcription, and interact with other regulatory proteins to form complex regulatory networks.
In contrast, ribosomes are responsible for protein synthesis and do not directly regulate gene expression. Plasmids are small, circular DNA molecules that are often found in bacteria and can carry additional genetic information, but they are not typically present in eukaryotic cells. Lactose is a sugar that can act as an inducer for gene expression in certain bacterial systems, such as the lac operon, but it does not directly regulate gene expression in eukaryotic cells.
♥️
