1. What is Life? ASTR 4: Life in the Universe

2. Discussion Topics Three Domains of Life Basic Cell Structure Macro-molecules Properties of Life

3. Three Domains of Life

4. Basic Cell Structure

5. Basic Prokaryotic Cell Structure

6. Basic Eukaryotic Cell Structure

7. Macro-molecules Proteins Nucleic Acids Carbohydrates Lipids

8. Proteins

12. Nucleic Acids

15. Carbohydrates (C:H:O=1:2:1)

16. Lipids

17. Chirality

18. Properties of Life Order Metabolism (Energy Utilization) Reproduction (Growth) Differentiation (Development) Communication Movement (Response to the Environment) Evolution

20. More Questions… How about Viruses, Viroids & Prions? Carbon-based Only? Closed System Only? What is the minimal definition of life? Human Coronavirus -- SARS Prion – Mad Cow Disease