Understanding Nucleic Acids Practice Test

The bulky two-ring structure of purines would cause too much hindrance in the inside of the helix.

Two purines could cause a bump in the DNA, causing problems with transcription and replication.

The functional groups at the end of one purine would not correctly match with the other purine.

Purine bases will never be found on opposite DNA strands, so they do not have the ability to pair with one another.