Читать книгу Astrobiology - Charles S. Cockell - Страница 54

How much of the preceding discussion on bonding types is applicable on a universal scale? We could probably confidently say that the major bonding types we have discussed are universal. They are shaped by fundamental interactions between electrons of different ions, atoms, and molecules. As we have already agreed that fundamental atomic structures are universal, then the bonding types available to construct life are also likely to be universal. However, how much of the detail on how these bonding types are used in different molecular structures is universal? Are we confident that ionic interactions between amino acids to make proteins are universal? Must all life contain proteins? Would all material involved in storing information about life (genetic material or its equivalent) use hydrogen bonding to hold together molecules that need to split in two and replicate? We have already explored some ideas about why life on Earth does not use metallic structures. Are those proposed reasons universal, or could we find aliens with steel bars for bones and skulls made of titanium? (Here I am referring to the process of natural selection, not technological augmentation, which, as we all know, can be used to put steel bars in bones.) As we discuss the major macromolecules of life in Chapter 4, continue to consider the question of the universality of the structure of life.

In the meantime, let us now continue to consider the basic behavior of matter.