45 DNA Replication Exercise B: DNA Replication (con\'t) Initiation of replicatio

Question

45 DNA Replication Exercise B: DNA Replication (con't) Initiation of replication (con't) 1. How would you convert a spring into a straight . . SSBP , Cytosine -Adenine . Guanine . Thymine piece of metal using the same approach as topoisomerase in DNA replication? -Helicase .. DNA Polymerase I . DNA Polymerase " @. DNA Polymerase ln . Uracil o-Deoxyribose +. Primase Ribose A-Ligase . Phosphate Telomerase Once the parental DNA strands are opened and stabilized, the enzyme primase adds a few ribonucleotides (R-nucleotides) to the template strands of the parental DNA (Fig. 6). These RNA nucleotides are primers allowing DNA Polymerase I// to attach. DNA Polymerase lll is the main workhorse of DNA replication, matching up D-nucleotides to the opened parental DNA strand. The RNA primer allows DNA Polymerase ll to attach and provides a hydroxyl (OH) group so the first D- nucleotide can be matched up with the parental strand. 2 Draw the RNA nucleotides 5' E Identify the function of the SSBPs (0). Fig. 6. Initiation of replication, part 2. Elongation stage of replication: leading strand vs. lagging strand Once DNA Polymerase Il is in place, primase is removed and new D-nucleotides can only be added to the 3' carbon of the deoxyribose in the parental strand. From the perspective of the parental strand new DNA grows from the 5' end of the nucleic backbone towards the 3' end, from 5'> 3' As helicase opens the DNA, DNA Polymerase Ill continually adds D-nucleotides in one direction. This strand is known as the leading strand. As helicase opens the double helix, the leading strand is continuously replicated by DNA Polymerase IlI. www.thebiologyprimer.com

Explanation / Answer

Ans 1) The structure of DNA is heavily coiled to each other and in order to unwind it, it requires the help of topoisomerase enzyme. Let us assume a spring which is heavily twisted and applying the concept of topoisomerase, we have to straighten it into metal piece. If we have to follow the same principle, we will break one strand of the wrapped strand of metal and rotate it around the other intact strand to help it unwind and this is followed by straigtening the piece into single metal. The bond between the spring is broken by introducing gaps and breaking a part of the strand and slowly uncoiling it.

Ans 2) After the unwinding of the double helical DNA, there must be a way to prevent the separated strands from coiling again. As soon as the DNA unwinds, the SSBs proteins bind to the single stranded regions of DNA and helps in stabilising the structure and prevent it form coiling back again.

Related Questions

Navigate

• Browse (All)
• Browse 4
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.