1. The Central Dogma
… From DNA to proteins

2. How your cell makes proteins…
The synthesis (production) of proteins:
2 phases
Transcription
Translation
DNA  RNA  Protein

3. Before making a protein…
Your cell must first make RNA
How does RNA differ from DNA?
DNA
RNA
Deoxyribose sugar
Ribose sugar
Thymine (T)
Uracil (U)
Double stranded
Single-stranded

5. Types of RNA Messenger RNA (mRNA) Transfer RNA (tRNA)
Carries instructions from DNA to ribosome and tells it what kind of protein to make
Transfer RNA (tRNA)
Brings amino acids to ribosomes during proteins synthesis
Ribosome RNA (rRNA)
Guides the translation of mRNA into protein
All are produced in the nucleus!

6. If the cell were Westlake…
Nucleus – Main office
Nucleolus – Mrs. Bates’ office
DNA – Mrs. Bates
Ribosomes – Cafeteria ladies
mRNA – that Mrs. Bates sends to the lunch ladies to tell them what to make

7. Transcription (DNAmRNA)
RNA molecules are produced by copying part of a DNA strand into a complementary sequence of RNA (remember – U replaces T!!)
The process is started and controlled by an enzyme called RNA polymerase

8. Transcription
Animation

9. Translation
The process of making proteins from mRNA – takes places in ribosomes
The sequence of mRNA bases determines the amino acid sequence of a protein
There are 20 amino acids

10. Translation
Each series of THREE (3) mRNA bases is called a CODON and corresponds to a specific amino acid
This is known as the genetic code
tRNA molecules carry an amino acid at one end and an ANTICODON at the other
The anticodon is made up of three bases that are complementary to codons on the mRNA strand
Ex: AUG on mRNA = UAC on tRNA

11. Steps of Translation 1. Initiation
Process begins at the start codon (AUG). AUG codes for the amino acid Methionine
Met will be the first amino acid in this sequence

12. Steps of Translation 2. Elongation
Individual tRNA molecules continue to carry amino acids to the ribosome and place them in the order determined by the mRNA sequence

13. Steps of Transloation 3. Termination
The process of translation is completed when the ribosome reaches any one of the three STOP codons on the mRNA strand
The stop codons are: UAA, UAG or UGA

14. Translation
Animation
Video Clip

15. Checkpoint:
If given the anticodon ACC which belongs to the amino acid tryptophan, what would be the DNA base code for this amino acid?

16. The Codon Wheel

17. The Codon Chart: