1. Translation

2. RNA  Polypeptide Translation is the process of making polypeptides from mRNA Occurs in a 5’  3’ direction

3. The genetic code? DNA sequences that have been transcribed into mRNA are read in three base segments (codons)

4. The Genetic Code The genetic code is nearly universal Shared by organisms from the simplest bacteria to the most complex animals The genetic code is degenerate Different codons code for the same amino acid

5. Codon Chart

6. Practice “Decoding base sequences” activity on pg. 120

7. Translation The next step of DNA  Protein is translation. We “translate” our message into a whole different language – PROTEINS What we need: mRNA “message” Ribosomes to “read” the message Ribosomes are made from protein and rRNA Amino Acids (the monomers of proteins) Carried on tRNA molecules

8. The Structure of Transfer RNA A C C Figure 17.14a Two-dimensional structure. The four base-paired regions and three loops are characteristic of all tRNAs, as is the base sequence of the amino acid attachment site at the 3 end. The anticodon triplet is unique to each tRNA type. (The asterisks mark bases that have been chemically modified, a characteristic of tRNA.) (a) 3 C C A C G C U U A A G ACA C C U * G C * * G UGU * C U * GA G G U * * A * A A G U C A G A C C * C GA G A G G G * * G A C U C * A U U U A G G C G 5 Amino acid attachment site Hydrogen bonds Anticodon A (b) Three-dimensional structure Symbol used in this book Amino acid attachment site Hydrogen bonds Anticodon A AG 5 3 35 (c)

9. tRNA activating enzymes A specific enzyme called an aminoacyl-tRNA synthetase Joins each amino acid to the correct tRNA (enzyme-substrate specificity) Phosphorylation occurs http://biology-forums.com/index.php?action=gallery;sa=view;id=430

10. Ribosomes The ribosomal subunits Are constructed of proteins and ribosomal RNA (rRNA) HW: Do the activity from the textbook on pg. 362 – 363. You can fill in the related portion in your booklets (pg 36). Figure 17.16a TRANSCRIPTION TRANSLATION DNA mRNA Ribosome Polypeptide Exit tunnel Growing polypeptide tRNA molecules E P A Large subunit Small subunit mRNA Computer model of functioning ribosome. This is a model of a bacterial ribosome, showing its overall shape. The eukaryotic ribosome is roughly similar. A ribosomal subunit is an aggregate of ribosomal RNA molecules and proteins. (a) 5 3

11. The ribosome has three binding sites for tRNA The E site The P site The A site Figure 17.16b EPA P site (Peptidyl-tRNA binding site) E site (Exit site) mRNA binding site A site (Aminoacyl- tRNA binding site) Large subunit Small subunit Schematic model showing binding sites. A ribosome has an mRNA binding site and three tRNA binding sites, known as the A, P, and E sites. This schematic ribosome will appear in later diagrams. (b)

12. Figure 17.16c Amino end Growing polypeptide Next amino acid to be added to polypeptide chain tRNA mRNA Codons 3 5 Schematic model with mRNA and tRNA. A tRNA fits into a binding site when its anticodon base-pairs with an mRNA codon. The P site holds the tRNA attached to the growing polypeptide. The A site holds the tRNA carrying the next amino acid to be added to the polypeptide chain. Discharged tRNA leaves via the E site. (c)

13. Translation (3.5.4)

15. Bonded amino acids

18. Protein destination? Ultimate destination of the protein is determined by the location of ribosome where it is produced Free ribosomes – Bound ribosomes –

19. Free Ribosomes Used to make proteins for use within the cell.

20. Polysomes mRNA + many ribosomes actively making polypeptides Do the DBQ on Electron Micrographs on pg. 118 – 119. http://www.nature.com/scitable/content/growing-polysomes-on-a-chromosome-from-e-27459

21. Bound Ribosomes Used to make protein for: secretion (export out of the cell) use in the ER, golgi-apparatus, lysosome, or plasma membrane

22. Bound Ribosomes

23. A “signal sequence” at the start of the newly-translated polypeptide attaches to a signal recognition protein. The signal recognition protein pauses translation until the protein becomes bound to a receptor on the ER membrane. Translation is restarted and the new polypeptide is moved into the lumen of the ER as it is made.

24. Bound Ribosomes

25. Prokaryotes No nuclear membrane, so… In prokaryotes, transcription is followed immediately by translation, as the mRNA is already present in the cytoplasm.

26. Bioinformatics Read pg. 368. What is meant by a BLAST search? What are conserved sequences? Why are conserved sequences useful for biologists?

27. Protein Structure https://prezi.com/znzdtanmmfae/macromolecules/

28. Protein Structure 1 o Structure: Sequence and number of amino acids in the polypeptide chain http://commons.wikimedia.org/wiki/File:Protein-primary-structure.png

29. Protein Structure 2 o Structure: Alpha-helices and beta-pleated sheets Stabilized by hydrogen bonds between amine and carboxyl groups of amino acid in different parts of the chain. http://www.abcte.org/files/previews/biology/s3_p2.html

30. Protein Structure 3 o Structure: R-group interactions Positively and negatively charged R-groups form ionic bonds Hydrophobic and hydrophilic orientations Polar R-groups form hydrogen bonds Disulfide bridges (covalent bonds) http://education-portal.com/academy/lesson/tertiary-structure-of-protein-definition-lesson-quiz.html

31. Protein Structure 4 o Structure: SOME proteins have quaternary structure if they consist of more than one polypeptide chain. Also can have the addition of non-polypeptide components called prosthetic groups to make a conjugated protein. Ex. Adding a heme group when forming hemoglobin Try the DBQ on Hemoglobin on pg. 371. http://swift.cmbi.ru.nl/gv/students/mtom/QUA_1.html

32. Check it out… Video : From DNA to protein http://www.youtube.com/watch?v=D3fOXt4MrOM CHECK IT OUT: http://learn.genetics.utah.edu/content/begin/dna/