2. Transcription and Translation DNA’s destiny!

3. What does DNA really do? The DNA code must code for something right??? So what IS IT???? The DNA code must code for something right??? So what IS IT???? The DNA alphabet essentially codes for amino acids The DNA alphabet essentially codes for amino acids Which are the building blocks for……. Which are the building blocks for…….PROTEINS!!!!!!!!!! This occurs in several organized steps IN 2 PHASES This occurs in several organized steps IN 2 PHASES

4. What is RNA?

5. From DNA to Protein: the 2 phases PHASE 1: PHASE 1: Transcription Transcription DNA IS TRANSCRIBED INTO READABLE FORM (mRNA) DNA IS TRANSCRIBED INTO READABLE FORM (mRNA) PHASE 2: PHASE 2: Translation Translation mRNA IS TRANSLATED (tRNA) TO CODE FOR AMINO ACIDS mRNA IS TRANSLATED (tRNA) TO CODE FOR AMINO ACIDS

6. Transcription: The Video Clip

7. Phase 1: Transcription Occurs INSIDE THE NUCLEUS Occurs INSIDE THE NUCLEUS 1. DNA strands separate 2. Complimentary RNA bases take their places along DNA with the help of enzymes RNA bases are A, C, G, and U (uracil) RNA bases are A, C, G, and U (uracil) U instead of T! U instead of T! This creates an mRNA strand This creates an mRNA strand Let’s see this in action! Let’s see this in action!

8. Phase 1: Transcription Let’s practice making a complimentary mRNA from a DNA strand! DNA mRNA C G A T T A G A T G C U A A U C U A

9. Proteins…the ultimate result Long chains formed by 20 different amino acids Long chains formed by 20 different amino acids Protein shape is determined by DNA sequence! Protein shape is determined by DNA sequence! DNA transcribed to mRNA DNA transcribed to mRNA mRNA is eventually translated by tRNA (transfer RNA) and codes for amino acids! mRNA is eventually translated by tRNA (transfer RNA) and codes for amino acids!

10. Protein Synthesis: The Video Clip

11. Proteins…the ultimate result 3 mRNA bases will code for a specific amino acid. 3 mRNA bases will code for a specific amino acid. Ex. GCU codes for Alanine Ex. GCU codes for Alanine This is called a CODON This is called a CODON Each amino acid has more than one codon! Each amino acid has more than one codon! Polypeptide: String of amino acids Let’s look at the mRNA we transcribed earlier! Let’s look at the mRNA we transcribed earlier!

12. Proteins…the ultimate result The strand we made earlier is: The strand we made earlier is: G C U A A U C U A If 3 bases code for an amino acid, how many amino acids are coded in our strand? If 3 bases code for an amino acid, how many amino acids are coded in our strand? 3 of course! G C U | A A U | C U A Alanine | Asparagine | Leucine Coding and stringing amino acids together is called TRANSLATION!

13. The Genetic Code!

14. Phase 2: Translation mRNA is shipped out of nucleus for translation mRNA is shipped out of nucleus for translation **Review** Which organelle is in charge of protein synthesis?? (Hint: very tiny little buggers) **Review** Which organelle is in charge of protein synthesis?? (Hint: very tiny little buggers)RIBOSOMES! mRNA binds to a ribosome for translation! mRNA binds to a ribosome for translation!

15. Phase 2: Translation 1. mRNA binds to ribosome 2. Ribosome translates the codons on the mRNA 3. This signals a tRNA to bring the correct amino acid 4. tRNA drops off the amino acid

16. Phase 2: Translation 5. Ribosome moves to next codon 6. Another tRNA comes with next amino acid 7. Amino acids are connected by PEPTIDE BONDS This continues until all of the mRNA has been read and a STOP codon is reached. This continues until all of the mRNA has been read and a STOP codon is reached. End result: a protein!!!!!!!!! End result: a protein!!!!!!!!! Let’s return to the transcription/translation site!