What is the definition of a dominant trait in biology? What is the difference between biology and AP biology? What is the difference between molecular biology and cell biology?
DNA gyrase, often referred to simply as gyrase, is an enzyme that relieves strain while double-strand DNA is being unwound by helicase. It is also known as DNA topoisomerase II. This causes negative supercoiling of the DNA. Bacterial DNA gyrase is the target of many antibiotics, including nalidixic acid, novobiocin, and ciprofloxacin.
A DNA fragment of a few base pairs up to â20 kb can be inserted into a plasmid vector. When such a recombinant plasmid transforms an E. coli cell, all the antibiotic-resistant progeny cells that arise from the initial transformed cell will contain plasmids with the same inserted sequence of DNA (Figure 7-3).