A. A macromolecule isolated from an extraterrestrial source superficially resembles DNA, but closer analysis reveals that the bases have quite different structures (Figure Q5–7). Bases V, W, X, and Y have replaced bases A, T, G, and C. Look at these structures closely. Could these DNA-like molecules have been derived from a living organism that uses principles of genetic inheritance similar to those used by organisms on Earth?

B. Simply judged by their potential for hydrogen bonding, could any of these extraterrestrial bases replace terrestrial A, T, G, or C in terrestrial DNA? Explain your answer.

Figure Q5–7

Transcribed Image Text:

HIC エー H 3 ZIC C Z V I T Z-I Z-I I Z-HO OI-Z Z-IZ Z-IC I -Z Z H -Z X I