1. Making Proteins: Translation Lecture #25 Honors Biology Ms. Day

2. REVIEW… Translation mRNA  polypeptide (protein)

3. Type of RNAFunction JobPicture mRNA (messenger RNA) Brings message from DNA (DNA instructions) to ribosome to make protein tRNA (transfer RNA) Transfers/moves amino acids to ribosomes rRNA (ribosomal RNA) Makes up ribosomes along with proteins

4. tRNA A cell translates mRNA message into protein with help from transfer RNA (tRNA) Each carries a specific amino acid “t” shape Carries amino acids Matches codons to anticodons

5. Ribosomes Help bind tRNA anticodons with mRNA codons during translation An t icodon ( t RNA) = codon (mRNA)

6. tRNA (with anticodons) mRNA (with codons) AMINO ACIDS

7. REVIEW…The Genetic Code It’s a table used that TRANSLATES RNA nucleotides called CODONS (or mRNA “letters”) into one of the 20 amino acids 3 letter mRNA “word” = 1 amino acid There are 4 different RNA “letters” that can be used A, U, C, and G

8. THE GENETIC CODE

9. Ribosomes There are 2 ribosomal subunits Constructed of proteins and ribosomal RNA or rRNA

10. Building a Polypeptide Translation can be divided into 3 phases Initiation Elongation Termination

11. Initiation of Translation initiation stage brings together mRNA tRNA bearing 1 st amino acid (“start”) called MET 2 subunits of a ribosome come together

12. Large ribosomal subunit Initiator tRNA mRNA mRNA binding site Small ribosomal subunit Translation initiation complex GDP GTP Start codon Met U A C A U G 3 5 5 3 3 5 3 5 Figure 17.17

13. Elongation Amino acids are added one by one to the preceding amino acid Peptide bonds are formed Amino acid

15. Termination of Translation When the ribosome reaches a stop codon on the mRNA There are 3 stop codons UAA, UAG, and UGA Release factor (protein) binds to stop codon (NOT tRNA)  polypeptide released

16. Termination of Translation Release factor Free polypeptide Stop codon (UAG, UAA, or UGA) 5 3 3 5 3 5

17. Figure 17.13 TRANSCRIPTION TRANSLATION DNA mRNA Ribosome Polypeptide Amino acids tRNA with amino acid attached Ribosome tRNA Anticodon mRNA Trp Phe Gly A G C A AA C C G U G GU U U GG C Codons 5 3 “EMPTY” tRNA

18. Polypeptide  3D Protein Primary Structure Amino acids is a row (LINEAR) Secondary Structure Amino Acids BEND and FOLD towards each other Tertiary Structure Amino acids BIND to each other 3D shape made Quartnary structure (only some) 2 or more polypeptides BIND to each other

19. 1 2 3 4

20. Translation (Protein Synthesis) Animation http://www.wisc- online.com/objects/index_tj.asp?objID=AP13 02 http://www.wisc- online.com/objects/index_tj.asp?objID=AP13 02 http://highered.mcgraw- hill.com/sites/0072437316/student_view0/cha pter15/animations.html# http://highered.mcgraw- hill.com/sites/0072437316/student_view0/cha pter15/animations.html# https://highered.mcgraw- hill.com/sites/0072507470/student_view0/cha pter3/animation__how_translation_works.htm l https://highered.mcgraw- hill.com/sites/0072507470/student_view0/cha pter3/animation__how_translation_works.htm l http://www.biostudio.com/demo_freeman_pro tein_synthesis.htm http://www.biostudio.com/demo_freeman_pro tein_synthesis.htm