1. Translation

2. Central Dogma
DNA
RNA
Protein

3. Translation The last step in the “central dogma” process
Transcription involves the conversion of mRNA base sequence into polypeptides
Polypeptides build proteins!
How do you get from 4 mRNA bases (A, U, C, G) to 20 different amino acids?

4. Triplet Code
Codon: sequence of three nucleotides that codes for a specific amino acid
Since there are 4 different bases, that means there are 64 possible codons and only 20 amino acids
Some codons will result in addition of the same amino acids
Also, there are three stop codons (signal the end of translation) and one start codon (signals the beginning of translation)

6. Triplet Code Codons must be read in the correct order
What could happen if the “reading frame” is changed during translation?
The wrong protein could be made
Stop codon could turn up early

7. Universal Genetic Code
Codons code for the same amino acid in almost every organism- from bacteria to fungi to humans.
Often referred to as “universal”
A gene will make the same amino acid, regardless of what organism it is in!

8. Translation Occurs in the cytoplasm
Small ribosomal subunit binds to mRNA strand
Remember we said that ribosomes build proteins? This is how!
Translation involves 2 types of RNA
Strand of mRNA as the “blueprint”
Transfer RNA (tRNA): “anticodons” bind to mRNA codons and bring appropriate amino acid

9. Translation The mRNA codon attracts a complementary tRNA anticodon
tRNA molecules each bring the appropriate amino acid
As translation proceeds, amino acids are bonded into a chain by peptide bonds
tRNA’s shift through 2 sites on the ribosome until a stop codon is reached, signaling the end of translation.