1. The Functions of DNA
Part 2

2. 2. Protein synthesis “Central dogma” (main idea) of molecular biology:
DNA RNA protein
One gene One protein
(We already know that proteins do the work to make all your traits, which make you YOU.)

3. Protein Synthesis Part I: Transcription
DNA RNA protein

4. What is RNA? RiboNucleic Acid How is that different from DNA?
Ribo- vs. Deoxyribo-

5. RNA vs. DNA
Double strand
Single strand

6. RNA vs. DNA con’t.
Different
sugars

7. RNA vs. DNA con’t.
Base difference:
DNA: thymine RNA: uracil (U)

8. What is the function of RNA?
To carry the genetic message from the nucleus to where it will be used in the cytoplasm
Why not just use DNA for that purpose?
DNA-double strand: can’t fit through nuclear pore;
RNA-single strand: fits through
DNA-master template: stays protected in nucleus
RNA-disposable: can always make more

9. Transcription
A gene on the DNA molecule unwinds

10. Transcription
2. RNA bases are attached to unraveling DNA strand (using RNA polymerase)

11. Transcription
3. RNA strand (called messenger RNA or mRNA) detaches from DNA and leaves nucleus to travel into cytoplasm

13. Why is transcription necessary?
DNA is double stranded and too big to leave nucleus through pores
DNA is the all-important master template and must stay protected. RNA is disposable

14. Practice transcription
TAC GAA CGA GTG
AUG CUU GCU CAC