1. 4/19/12 Objective: Understand and explain the field of astrobiology
Warm-Up: List three of water’s special properties

2. Water
Water’s high specific heat means that the chemical reactions important to life can be “insulated” by water
Another reason water is good for living things is because water can dissolve most substances
This means water can hold and transport nutrients for organisms
Adhesion and cohesion allow water to move easily through organisms

3. Organic Molecules
In science, the word “organic” means anything that is alive or a part of a living thing
Every organic molecule contains the elements carbon and hydrogen
Other elements that can be found in organic molecules are oxygen, nitrogen, phosphorous, and sulfur
There are four important organic molecules

4. The Four Organic Molecules
Proteins
Proteins are made of smaller molecules called amino acids
Lipids (Fats)
Carbohydrates (Sugar & Starch)
Nucleic Acids
DNA and RNA; these molecules carry your genetic information
Made of smaller molecules called nucleotides

5. Where did these molecules come from?
The scientists Miller and Urey demonstrated that the atmosphere of early Earth could have produced some amino acids
Other similar experiments have shown that the chemistry of early Earth could also have produced some nucleotides
But other scientists think that these organic molecules might have been carried to Earth by comets and/or meteors

6. Astrobiology
Astrobiologists study the possibility that life might exist other places in the universe
Astrobiologists have found some organic molecules on meteors that hit Earth’s surface
These findings have caused some scientists to hypothesize that these meteors were the source for the first organic compounds on Earth