Chapter 27, Problem 1Q

To determine

The meaning of “life as we know it”, and the reason that astrobiologists suspect that extraterrestrial life is likely to be of this form.

Answer to Problem 1Q

“Life as we know it” means that an organism must be composed of mainly organic (carbon- based) molecules and extraterrestrial life is likely to be of this form because these are the basic elements for the existence of any kind of life.

Explanation of Solution

The statement “life as we know it” means that organism must be composed of mainly organic (carbon- based) molecules such as oxygen, carbon, hydrogen and nitrogen. They are the most abundant element present in any organism similarly as they do in life on Earth.

Abundance of liquid is also one of the main substances for the survival of life such as water on Earth. Liquid is required so that biochemical reaction can occur easily.

Life can only exist in places where there is chemical disequilibrium maintained by natural conditions. Chemical disequilibrium is important because it offers the potential for providing chemical energy for life and it can show how energy is transformed in chemical reactions.

Carbon is also one of the most important elements due to its complex chemical behavior and therefore, it is the basis of biochemical process which is known as life.

Astrobiologists suspect that extraterrestrial life is likely to be of this form because these are the basic elements for the existence of any kind of life.

Conclusion:

Thus, “life as we know it” means that organism must be composed of mainly organic (carbon- based) molecules and extraterrestrial life is likely to be of this form because these are the basic elements for the existence of any kind of life.