Final answer:
Various substances can inhibit DNA and RNA synthesis, affecting gene expression. Antibiotics like anthracyclines and dactinomycin bind to DNA and inactivate it, preventing RNA synthesis. Actinomycin-D and rifampicin also hinder transcription. These inhibitors target specific steps involved in DNA and RNA synthesis.
Step-by-step explanation:
DNA and RNA synthesis can be inhibited by various substances. Antibiotics such as anthracyclines, dactinomycin, and bleomycin can bind to DNA and inactivate it, preventing the synthesis of RNA. Actinomycin-D and acridine also inhibit DNA-directed RNA synthesis. Rifampicin can bind to the beta-subunit of RNA polymerase, preventing initiation of transcription. These inhibitors affect the processes involved in DNA and RNA synthesis, thus interfering with gene expression.