Chapter #7 Requirements for Extraterrestrial Life.


1. What are the general requirements (suggested by George Wald) that can be placed on a planet, which might be necessary for the existence of life? (page 110)

2. What is the one single most stringent requirement that must be present for the existence of terrestrial life? (page 110)

3. What are some of the other liquids that could serve as possible candidates for supporting life? Why are these liquids less likely than water to serve as the liquid that allows for the development of terrestrial life? (page 111)

4. What are the three physical properties of water make it particularly well suited for sustaining terrestrial life? (page 110 &endash; 112)

5. What would happen to cells with membranes composed of non-polar molecules if they were placed in ethane or methane lakes of another planet? (page 113)

6. Which 21 of the 92 naturally occurring elements in the universe play a major role in terrestrial life? (page 113)

7. What are the four most significant biogenic elements? What is significant about how these elements interact with other atoms during chemical reactions? (page 114)

8. Why is silicon not a suitable alternative for carbon in serving as the central elemental basis for terrestrial like life? (page 114)

9. What is (approximately) the maximum wavelength of light that is capable of breaking the bonds of organic molecules? Would light with a shorter wavelength also be capable of breaking these bonds? Explain your reasoning. (page 116 &endash; 117)