1. Four processes were needed for the spontaneous origin of life on Earth:
Non-living synthesis of simple organic molecules
Assembly of these molecules into polymers
Origin of self replicating molecules that made inheritance possible
Packaging of these molecules into membranes with an internal chemistry different from their surroundings

2. In modern living systems, information flows from

3. WHAT IS RNA?

4. Each consists of a base, a ribose sugar, and a phosphate group.
One of the four major biomolecules (along with lipids, carbohydrates and proteins)
What is RNA?
Ribonucleic acid is a nucleic acid
RNA is essential for all known forms of life.
Like DNA, RNA is made up of a long chain of nucleotides.
Each consists of a base, a ribose sugar, and a phosphate group.

5. How is RNA different than DNA?
RNA contains the sugar ribose, while DNA contains the slightly different sugar deoxyribose
RNA has the base uracil while DNA contains thymine.
Unlike DNA, most RNA molecules are single-stranded and can adopt very complex three-dimensional structures.

7. REMEMBER: In modern living systems, information flows from

8. DNA  RNA  Protein This sequence probably developed in stages

9. RNA-First Hypothesis
Through the Wormhole video clip #2i in class 20:00 -27:00
The first genetic information and enzymes were RNA molecules
Why RNA? RNA can act as a catalyst to:
Bind amino acids together to form proteins
Replicate itself to create more RNA (animation #1)

10. RNA can be transcribed to DNA
This could have given rise to the first DNA

12. DNA is more stable than RNA and eventually took over carrying the genetic information

13. Arguments for the RNA First hypothesis
In Miller’s experiments, ribose was created and deoxyribose was harder to produce.
RNA has a simpler structure then DNA.
RNA exists in viruses (and no DNA)
It has been proved experimentally that RNA has catalytic functions (it is a catalyst)
The DNA-protein system cannot work without RNA.