In the belowreplication process, what enzyme is used to put what building blocks together?

Question

How is complimentary base pairing used to assure proper placement of the building blocks? What bonds are formed to hold the structure together permanently? What enzyme creates this bond?

Transcription of DNA into mRNA involves only one change: All T's become U's. This is because RNA uses the base Uracil (U) rather than Thymine (T), although their structures are very similar. 

 

One strand of DNA read from left to right (5'- to 3'-): 

A A T G C C G T A T A G C T C A T G C T A

The same strand read from right to left (3'- to 5'-): 

T T A C G G C A T A T C G A G T A C G A T

 

One RNA strand produced will read: 

A A U G C C G U A U A G C U C A U G C U A

The 2nd RNA strand produced will read: 

U U A C G G C A U A U C G A G U A C G A U

Answer 1

Complimentary base pairing refers to utilizing the matching pairs of purine and pyrimidine molecules, A-T (A-U in RNA), and G-C to ensure that the molecules are connected in the correct way. Due to the structure of the purine and pyrimidine rings as well as the number of hydrogen bonds each pair can make, A will only pair with T in DNA and U in RNA, just like G will only pair with C. This specificity for the matching pair ensures that DNA's information stays conserved in the correct fashion. During transcription, RNA polymerase is the enzyme that reads the DNA template strand and constructs the mRNA. It does so by connecting nucleotides together via a phosphodiester bond, which connects the phosphate group of one nucleotide to the sugar of another nucleotide.