The number of phosphodiester and hydrogen bonds formed during preparat...
In the process of preparing recombinant DNA (rDNA) using the enzyme EcoRI, a single phosphodiester bond is formed between the two strands of DNA. EcoRI is a restriction enzyme that cleaves DNA at a specific sequence, known as the recognition site, and generates two single-stranded DNA ends. These ends can then be ligated (joined) together using a ligase enzyme, which forms a phosphodiester bond between the two strands.
During the preparation of rDNA using EcoRI, a total of 2 phosphodiester bonds are formed: one between the two strands of DNA being ligated together, and one between the ligated DNA and the EcoRI recognition site.
In addition to the phosphodiester bonds, a number of hydrogen bonds are also formed between the two strands of DNA being ligated together. The number of hydrogen bonds depends on the sequence of the DNA and the specific base pairs that are formed.
In general, the number of hydrogen bonds formed between two DNA strands is 8 per base pair. Therefore, the total number of hydrogen bonds formed during the preparation of rDNA using EcoRI will depend on the number of base pairs being ligated together.
Option (4) 4 & 8 is the correct answer. This represents the formation of 4 phosphodiester bonds (2 between the two strands of DNA and 2 between the ligated DNA and the EcoRI recognition site) and 8 hydrogen bonds per base pair.