1. Protein Synthesis Step 2: Translation

2. Review Protein Synthesis: The process by which the message of DNA is used to make proteins Step 1: Transcription ◦ Takes place in the nucleus ◦ Changes DNA to mRNA ◦ Base Pairs: A-U and C-G

3. Step Two: Translation “ Step Two: Translation “to decode or decipher the meaning of” Now that our mRNA molecule has been made, it’s time for its message to be made into a protein sequence. How does the mRNA sequence translate into an amino acid sequence?

4. Step Two: Translation Problem: ◦ There are 20 different amino acids. ◦ There are 4 RNA bases. pheilevalproalahisasnaspcysarg leumetserthrtyrglnlysglutrpgly A T C G

5. Step 2: Translation Translation in 3 steps: 1.mRNA leaves the nucleus and finds a ribosome in the cytoplasm 2.tRNA brings amino acids to the ribosome 3.rRNA joins the amino acids together by matching the codes between mRNA and tRNA

6. Ribosome (rRNA) tRNA

7. Step Two: Translation Watch this simplified animation: http://www.stolaf.edu/people/giannini/flasha nimat/molgenetics/translation.swf Watch the more complex animation! http://www- class.unl.edu/biochem/gp2/m_biology/ani mation/gene/gene_a3.html http://www- class.unl.edu/biochem/gp2/m_biology/ani mation/gene/gene_a3.html

8. Step Two: Translation 1. So how do you exactly go about determining what protein your cells are going to make? 2. FIRST, divide the mRNA sequence into codons. ◦ Codons are three-base sections of mRNA: AUG|CGU|ACU|GAU|CGU|UCA|GAU|UGA

9. Step Two: Translation 2. Since each 3-letter combination “codes” for an amino acid, you need to figure out what amino acid matches up with each codon: ? AUG|CGU|ACU|GAU|CGU|UCA|GAU|UGA

10. Use a Codon Chart!

11. Step Two: Translation 2. Since each 3-letter combination “codes” for an amino acid, you need to figure out what amino acid matches up with each codon: met AUG|CGU|ACU|GAU|CGU|UCA|GAU|UGA ?

12. Step Two: Translation 2. Since each 3-letter combination “codes” for an amino acid, you need to figure out what amino acid matches up with each codon: met AUG|CGU|ACU|GAU|CGU|UCA|GAU|UGA

13. Important Codons/Amino Acids! CodonAmino Acid Signal AUGMethionineSTART UAANoneSTOP UAGNoneSTOP UGANoneSTOP

14. Ribosome (rRNA) tRNA

15. How does tRNA know where to go? tRNA has an anticodon that coordinates with the codon on mRNA Anti-codon Anti-codon and codon pair up!

16. RECAP: 1. DNA is transcribed into mRNA in the nucleus. 2. The mRNA leaves the nucleus and enters the cytoplasm. 3. The protein is translated from the mRNA sequence using tRNA and amino acids.