Question

In order for DNA to replicate in a semi-conservative manner, what must occur?

1. The double stranded parent DNA molecule must be separated by breaking the hydrogen bonds between the nitrogenous bases
2. Both parent strands of DNA must serve as a template for the synthesis of the new strands
3. The parent strands of DNA must re-anneal after serving as a template for the synthesis of new DNA.

Answer 1

DNA replication in a semi-conservative manner involves separating the parent DNA strands, using each as a template for forming new strands, and re-annealing to form two identical DNA molecules with one original and one new strand each.

Step-by-step explanation:

In order for DNA to replicate in a semi-conservative manner, several steps must occur:

1. The double stranded parent DNA molecule must be separated by breaking the hydrogen bonds between the nitrogenous bases. This is accomplished by the enzyme helicase, which unwinds the DNA and splits apart the two strands.
2. Both parent strands of DNA serve as templates for the synthesis of new DNA strands. Each of the separated strands attracts new complementary nucleotides and is copied by the enzyme DNA polymerase.
3. After the new strands are synthesized, the parent strands re-anneal with the newly synthesized strands, forming two DNA molecules. Each of these has one parental strand (the original or 'old' strand) and one newly synthesized strand.

The result of this process is the formation of two identical double-helix DNA molecules, each containing one strand from the original DNA molecule and one new strand. This semi-conservative method of replication ensures the genetic information is accurately passed on to the daughter cells.