1. Stephen Eikenberry 16 January 2013 AST 2037
Life on Earth - II
Stephen Eikenberry
16 January 2013
AST 2037

2. RNA Single-stranded ribonucleic acid Similar in many ways to DNA
Several types of RNA commonly used in life
mRNA takes the DNA code “message” to places where proteins are made (“ribosomes”)
rRNA actually carries out the protein assembly in ribosomes
It appears that some viruses may use RNA for their genetic code

3. Cells: Basic Units of (most) Life
Smallest units of independent life here on Earth

4. Prokaryotic Cells Cells without nuclei
Typically considered “primitive” – i.e. bacterium

5. Eukaryotic Cells – Animals
With nucleus – “Advanced”
This one is an animal cell

6. Eukaryotic Cells – Plants
With nucleus – “Advanced”
This one is a plant cell
Note:
Cell Wall
Chloroplasts

7. Multi-cellular Life More than one cell
But, not so many you can’t count them easily!

8. Complex plants

9. Complex animals

10. Complex animals

11. Summary Tremendous commonality amongst a huge range of life on Earth
Under the microscope, hard to really tell one human cell from a jellyfish cell from a bacterium from a tree – basic features are the same
Also, chemical makeup (all DNA; all L-Alanine even)
Suggests a common origin …