An A-T base pair is stabilized by only two hydrogen bonds. Hydrogen-bonding schemes of very similar strengths can also be drawn between other base combinations that normally do not occur in DNA molecules, such as the A-C and the A-G pairs. What would happen if these pairs formed during DNA replication and the inappropriate bases were incorporated? Discuss why this does not often happen.

The best answer to the question: What would happen if these pairs formed during DNA replication and the inappropriate bases were incorporated? Discuss why this does not happen, would be:

1. The direct result of the formation of bonds between incorrect bases would be the formation of kinks in the chain that would lead to clumping of the molecule and the possible rupture and disassembling of the helix. The reason for this is that these base pairings are coordinated in such a way that their molecular structure allows the DNA molecule to assume its double-helical formation. If the base pairings were changed, then the structure would not be assumed and DNA would not be fully functional.

2. This does not happen because when DNA is synthesized, and the bases are paired up, there are several enzymes and mechanisms that constantly monitor the correct base pairing and when an abnormal one is formed, it is corrected and taken out of the formation. If more than one base pairing is abnormal, then, these mechanisms will ensure the destruction and re-formation of DNA strands that can be fully functional.

Sometimes, however, errors in DNA formation can be made and base pairs may be mismatched, which will produce a cell's genetic material to malfunction. This is the beginning stage of such diseases as cancer.