Explain why both parental DNA strand may be used to serve as a template for replication?

Question

How does DNA's structure allow for this phenomenon to occur?

Answer 1

I'm going to assume you are talking about the semi-conservative nature of DNA replication. A DNA molecule is comprised of two strands. Each strand runs anti-paralell to each other 5' (five prime) to 3'. DNA polymerase adds new bases to only the three prime end. The strand in the parental DNA that runs 5' to 3' has its bases added complementary in a linear motion, this is called the leading strand. The parental strand of DNA that runs 3' to 5' is complemented by DNA polymerase in a jagged fashion. What happens is DNA polymerase moves down stream on the lagging strand and complements bases on the 3' end. The result is multiple fragments of new DNA. These fragments, discovered by Okazaki, and named in his honor, are bound back together by DNA ligase. The result is each daughter strand of DNA containing one new piece and one old piece.

Answer 2

When the hydrogen bonds between the nitrogen bases are "unzipped" so replication can progress:

1. the only nucleotides that will match the unbonded nitrogen bases are the ones that have the right shape to fit, so the strand is gradually matched up and completed by the proper nucleotides (AT and CG)
2. Whether its a coding section or a noncoding section doesn't make any difference. Both sides are essential to make a complete DNA molecule.

The two new DNAs made during replication each have one original strand and one newly-assembled strand. The original strand in each new DNA acted as a pattern or template for the new building blocks to match.

Answer 3

For DNA replication to be deemed successful, the end products of replication are two identical double stranded DNA molecules derived from one double stranded DNA molecule. In order to do so, cells have used the technique of semi conservative replication whereby in each of the products, one strand is the original strand (parental strand) and the other is a newly synthesised one ( daughter strand ). This is to make full advantage of the fact that DNA is made up of sequence of nucleotides with only four different bases and their specificity in binding to each other (i..e. adenine binds only to thymine; cytosine binds only to guanine). Hence, by using each of the parental strands as a template, a daughter strand can be synthesised by complementary base pairing. 2. Structure of DNA is a double stranded helix with an origin of replication. At this origin, the hydrogen bonds can be broken by DNA helicase, allowing BOTH strands to be exposed to DNA Polymerase III which adds free deoxyribonucleotides to the growing strands by complementary base pairing.

Answer 4

because... both strands have different nucleotide sequences...hence able to code different mRNA, hence different products.