Fluоrоquinоlones аre synthetic аntibiotics thаt are effective against a wide variety of bacterial infections by targeting key bacterial enzymes involved in DNA replication and transcription. The primary target of fluoroquinolones is DNA gyrase (topoisomerase II) and, in some bacteria, topoisomerase IV. DNA gyrase introduces negative supercoils into bacterial DNA, which is crucial for relieving the tension generated during the unwinding of the double helix for processes like replication and transcription. Fluoroquinolones function by binding to the DNA-topoisomerase complex, stabilizing the intermediate state in which the enzyme has cleaved the DNA strands but has not yet re-ligated them. This prevents the resealing of the DNA, leading to the accumulation of double-strand breaks in the bacterial chromosome, which ultimately results in cell death. Topoisomerase IV, another target of fluoroquinolones, is responsible for the decatenation (separation) of linked daughter chromosomes following replication. Inhibition of this enzyme results in the failure of proper chromosome segregation during bacterial cell division, contributing to the bactericidal effects of fluoroquinolones. The selectivity of fluoroquinolones stems from the structural differences between bacterial and eukaryotic topoisomerases, allowing these drugs to specifically target bacterial enzymes while sparing human cells. What is the mechanism of action of Fluoroquinolones?
Use the infоrmаtiоn given аbоut the аngle θ, 0 ≤ θ ≤ 2π, to find the exact value of cos (2θ). tan θ = , π < θ