Читать книгу Astrobiology - Charles S. Cockell - Страница 95

1 Discuss the common molecular features of proteins, carbohydrates, and nucleic acids. How might such features be used to search for life elsewhere?

2 Life requires CHNOPS elements, but most living things also require some other elements. Describe the use of two other elements in living things.

3 Explain in simple terms how information is encoded in DNA and how the structure of that molecule allows for the information to be replicated.

4 Contrast the chemical steps in the assembly of proteins and carbohydrates. What are the similarities and differences?

5 We are composed mainly of L-amino acids and D-sugars. Why do you think life has this chiral preference? Use your knowledge of chemistry and astrochemistry to discuss whether you think this arrangement would be universal in all life (you might like to return to this question after you have read Chapter 10).

6 Describe two atomic features of carbon that make it a good element from which to build complex chained molecules in life. Contrast these features to silicon.

7 “Silicates have such astonishing molecular diversity that I see no reason why living things could not be made from minerals and rocks.” Discuss this point of view.

8 “Water is chemically fine-tuned to be perfect for living things.” Critique this statement.