2. 8.5 Translation Wed., 10/26 Write Questions & ANSWERS! Wed., 10/26 Write Questions & ANSWERS! 1.REPLICATE this DNA: A G G T C A T G C 2. TRANSCRIBE this DNA: A G G T C A T G C A G G T C A T G C 3. Does DNA stay in the nucleus? 4. Does RNA stay in the nucleus?

3. 8.5 Translation

4. So what did you learn yesterday??? replication transcription translation

5. 8.5 Translation 8.5 Key Concept: Translation converts an mRNA message into a polypeptide, or protein. Translation converts an mRNA message into a polypeptide, or protein.

6. 8.5 Translation Protein “Synthesis” What does this MEAN????? What does this MEAN????? Making proteins! Making proteins!

7. 8.5 Translation www.classzone.com Let’s do this!!! Let’s do this!!!

8. 8.5 Translation Amino acids are coded by mRNA base sequences. Translation converts mRNA messages into polypeptides. Translation converts mRNA messages into polypeptides. A codon is a sequence of three nucleotides that codes for an amino acid. A codon is a sequence of three nucleotides that codes for an amino acid. codon for methionine (Met) codon for leucine (Leu)

9. 8.5 Translation The genetic code matches EACH codon to its amino acid or function. The genetic code matches EACH codon to its amino acid or function. –three stop codons –one start codon, codes for methionine The genetic code matches each RNA codon with its amino acid or function. What amino acid is coded by GGA?........UGG……ACU?

10. 8.5 Translation A 3-nucleotide sequence; CODES for an amino acid! Signals start of translation; codes for methionine Signals STOP of translation Set of 3 nucleotides, read in order

11. 8.5 Translation A change in the order in which codons are read changes the resulting protein. A change in the order in which codons are read changes the resulting protein. Regardless of the organism, codons code for the same amino acid!!!! Regardless of the organism, codons code for the same amino acid!!!!

12. 8.5 Translation Ribosomes consist of two subunits. Ribosomes consist of two subunits. –The large subunit has three binding sites for tRNA. –The small subunit binds to mRNA. What is the function of mRNA? Site for translationSite for translation rRNA & proteinsrRNA & proteins Catalyzes bonds between amino acidsCatalyzes bonds between amino acids

13. 8.5 Translation Amino acids are linked to become a protein. An anticodon is a set of 3 nucleotides that is complementary to an mRNA codon. An anticodon is a set of 3 nucleotides that is complementary to an mRNA codon. An anticodon is carried by a tRNA. An anticodon is carried by a tRNA. Carries amino acids from cytoplasm to ribosomeCarries amino acids from cytoplasm to ribosome 1 end: anticodon1 end: anticodon 1 end: amino acid1 end: amino acid

14. 8.5 Translation Set of 3 nucleotides, read in order A 3-nucleotide sequence; CODES for an amino acid! Signals start of translation; codes for methionine Signals STOP of translation 3 nucleotides on tRNA, bind to complementary mRNA Site for translation rRNA & proteins Catalyzes bonds between amino acids Carries amino acids from cytoplasm to ribosome 1 end: anticodon 1 end: amino acid Codons “code” for same amino acids in almost ALL organisms!

15. 8.5 Translation Ribosome assembles @ start codon Complementary tRNA anticodon pairs up to mRNA codon in the ribosome

16. 8.5 Translation For translation to begin, tRNA binds to a start codon and signals the ribosome to assemble. For translation to begin, tRNA binds to a start codon and signals the ribosome to assemble. –A complementary tRNA molecule binds to the exposed codon, bringing its amino acid close to the first amino acid. What is the function of mRNA?

17. 8.5 Translation tRNAs keep bringing amino acids to ribosome, which moves down mRNA Ribosome forms peptide bonds b/w amino acids & breaks bond w/its tRNA

18. 8.5 Translation –The ribosome helps form a polypeptide bond between the amino acids. –The ribosome pulls the mRNA strand the length of one codon.

19. 8.5 Translation Keeeeeeeeeeps going til the ribosome reaches the STOP codon!

20. 8.5 Translation –The now empty tRNA molecule exits the ribosome. –A complementary tRNA molecule binds to the next exposed codon. –Once the stop codon is reached, the ribosome releases the protein and disassembles. What is the function of ribosomes?

21. 8.5 Translation