What is the function of DNA ligase and DNA Helicase?

Answer 1

helicases are necessary for unwinding double stranded DNA. in order to replicate its DNA, the cell must first unwind the two strands. once the the two strands have been separated enzymes such as DNA polymerase and RNA polymerase can act on the single stranded DNA.

DNA polymerase creates a strand of DNA from a template strand of DNA. it is used to create a new copy of the DNA. In order to begin DNA synthesis, a primer is necessary. The primer is a short oligo nucleotide fragment that hybridizes to the template strand of DNA (the strand which is to be copied). Once the primer is hybridized, the DNA polymerase can extend the primer and add nucelotides in a Watson-crick base pairing fashion. DNA polymerases always extend the primer in the 5' to 3' direction.

RNA polymerases are used to transcribe genes from DNA. Transcribtion is the process of making an RNA copy of information encoded in DNA. Once a gene is transcribed and a messenger RNA (mRNA) is produced, that mRNA can leave the nucleus to be translated into a protein by the ribosome. RNA polymerases work in a somewhat similar fashion to DNA polymerases, save for the fact that they produce RNA from DNA, instead of producing a new copy of the DNA.

Answer 2

DNA Polymerase III adds new nucleotides to the strand being created. DNA Polymerase I replaces the primers with DNA nucleotides. Ligase joins the fragments together.

Answer 3

during DNA replication,the enzyme helicase separates the two strands of DNA,

while enzyme ligase joins the ocazaki fragments.

Answer 4

They are both enzymes that are used in the process of making copies of DNA. Helicase splits the double-stranded helix apart so that the polymerase can start to produce the copies.