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Translation: mRNA to Polypeptide Conversion

Understand the process of translation, converting mRNA messages into polypeptides or proteins. Learn about codons, anticodons, and the genetic code.

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Translation: mRNA to Polypeptide Conversion

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  1. 8.5 Translation 2.1 Atoms, Ions, and Molecules • Set up Cornell Notes on pg. 7 • Topic: 8.5 Translation • Essential Question: • Explain the connection between a codon and an amino acid. • Suppose a tRNA molecule had the anticodon AGU. What amino acid would it carry? • Explain the connection between a codon and an amino acid. • Suppose a tRNA molecule had the anticodon AGU. What amino acid would it carry? KEY CONCEPT Translation converts an mRNA message into a polypeptide, or protein.

  2. p.6

  3. KEY CONCEPT Translation converts an mRNA message into a polypeptide, or protein.

  4. REVIEW: • Transcription makes three types of RNA. • Messenger RNA (mRNA) which was transcribed from DNA, carries the message that will be translated to form a protein. • Ribosomal RNA (rRNA) forms part of ribosomes where proteins are made. • Transfer RNA (tRNA) brings amino acids from the cytoplasm to a ribosome.

  5. What do you think of when you hear the word translation? • We usually think of translating one language into another • Hello=Hola in Spanish • Are the “words” exactly the same? • But, do they mean the same thing? Do they have the same message?

  6. Translation is a process that converts a message from one “language” into another. Hey, I know a joke! A squirrel walks up to a tree and says, "I forgot to store acorns for the winter and now I am dead." Ha! It is funny because the squirrel gets dead.

  7. Translation converts mRNA messages into polypeptides which make proteins. • mRNA can be translated into 20 different amino acids

  8. How can just four nucleotides (A, U, C, and G) be translated into so many different amino acids? • The same way 26 letters of the alphabet can be translated into so many words. • ape • pea The four letters of RNA are put together in different combinations to form many different “words” • A U C G

  9. codon for methionine (Met) codon for leucine (Leu) These “words” are called codons • A codon is a sequence of three nucleotides that codes for an amino acid. Please draw and label this picture (top of pg. 6)

  10. Separate this frame into “codons”: THECATATETHERAT SISATETHEPIE HISDOGWASHOT HERFATCATSAT

  11. Separate this frame into “codons”: THECATATETHERAT THE CAT ATE THE RAT SISATETHEPIE SIS ATE THE PIE HISDOGWASHOT HIS DOG WAS HOT HERFATCATSAT HER FAT CAT SAT

  12. The Start codon codes for the start of a gene segment • AUG • Three stop codons code for the end of a gene segment • UAG • UAA • UGA

  13. . • The genetic code matches each codon to its amino acid or function. • 1st two nucleotides are the most important

  14. Tell me what these genetic codes code for (middle pg. 6) Codon Amino Acid • GCC • AAA • AGC • UAG • AUA • AAU • GCA • CCG • UCA • AGG

  15. GCC- Alanine (Ala) • AAA- Lysine (Lys) • AGC- Serine (Ser) • UAG- stop codon • AUA- Isoleucine (Iso) • AAU- Asparagine (Asp) • GCA- Alanine (Ala) • CCG- Proline (Pro) • UCA- Serine (Ser) • AGG- Arginine (Arg)

  16. A change in the order in which codons are read changes the resulting protein. Please use your genetic code sheet to identify the amino acid for each codon Draw/Label each reading frame on the bottom of p. 6

  17. A change in the order in which codons are read changes the resulting protein.

  18. RANTHEFATCATSATONAHATHISSISWASMAD RANTHEFATCATSATONAHATHISSISWASMAD RANTHEFATCATSATONAHATHISSISWASMAD

  19. Regardless of the organism, codons code for the same amino acid.

  20. An anticodon is a set of three nucleotides that is complementary to an mRNA codon. Anticodon: AUG Codon: UAC • carried by a tRNA (transfer RNA).

  21. Codon to Anticodon practice (mRNA  tRNA) mRNA Codon AUG GUA AAA UUU AAU GGC UAG tRNA Anti-codon UAC CAU UUU AAA UUA CCG AUC

  22. Update Notebook 1: Double-helix coloring sheet 2: Replication pictures/replication practice 4:Transcription pictures 6: Genetic Code

  23. Ribosomes consist of two subunits. • The large subunit has three binding sites for tRNA. • The small subunit binds to mRNA.

  24. Protein Synthesis Video • Transcription 2m 50s • Translation 4m 47s

  25. Classwork (246-247) • Using p. 246-247 please take notes of what is happening in each part of translation • NOTICE there are edited versions of the pictures on your hand out, you will need to READ each step and closely analyze your picture in order to correctly establish what is happening in each picture • You will need 3 colors to color and make a key • Color 1- mRNA w/ codon • Color 2- tRNA (body/anticodon) • Color 3- Amino Acids

  26. Get 3 colors • Color 1- mRNA w/codons • Color 2- tRNA (body/anticodon) • Color 3- Amino Acid

  27. 1. tRNA binds to a start codon(AUG) and signals the ribosome to assemble. Amino acid AUG Start codon

  28. 2. A complementary tRNA anticodon binds to the exposed codon

  29. 3. The ribosome helps form a polypeptide bond between the amino acids. • The ribosome pulls the mRNA strand the length of one codon.

  30. 4. The now empty tRNA molecule exits the ribosome. • A complementary tRNA molecule binds to the next exposed codon.

  31. 5. This continues until a stop codon is reached (UAG, UAA, or UGA) -The ribosome releases the completed polypeptide chain, now a protein, and disassembles. Finished PROTEIN

  32. Protein Synthesis: Comparison of Primate DNA • Below each DNA sequence TRANSCRIBE the DNA strand into its complementary mRNA strand • Highlight each base that is different in comparison to the human’s DNA Ex: DNA: Human TTT DNA: Gorilla TTA 3. Using each of the completed mRNA strands from above, use your genetic code sheet to TRANSLATE each mRNA codon into its amino acid 4. Highlight each amino acid that is different in comparison to our human amino acids Ex: Protein: Human Asp. Protein: Gorilla Lys.

  33. 8.4-5 Protein Synthesis 2.1 Atoms, Ions, and Molecules • Set up Cornell Notes on pg. 9 • Topic: 8.4-5 Protein Synthesis • Essential Question: • NO EQ

  34. Notebook Check due Friday 1:            DNA Double Helix Coloring (10) 2:            EQ/Review ?s (1-3)/DNA molecule pic/Replication pictures  (20) 3:            8.3 Notes/?s (15) 4:            EQ/EQ/Central Dogma pic/ DNA vs. RNA/ Replication vs. Transcription Dub Bub/ Transcription pictures (30) 5:            8.4 Notes/ ?s (15) EQ/EQ/ Codon pic/ Codon translation (1-10)/ Reading frame pics/ Genetic Code/ Translation pictures (30) 7:            8.5 Notes/ ?s (15) 8:            Protein Synthesis: Comparison of Primate DNA (30) 9:            Protein Synthesis in a “nutshell”/ Protein Synthesis ?s (10) 10           EQ/P2P/Point and Frameshift mutation pics (10) 11           8.7 Notes/?s (15) Total                      /200

  35. P.9

  36. Protein Synthesis in a Nutshell (Top ½ p. 9) Replication DNA A A G A C G T A G DNA ______ ______ _______ (transcribe this piece) Transcription mRNA ______ ______ _______ (translate this piece) Translation tRNA ______ ______ _______ codons ___ ___ Amino Acids ___ anticodon Finished Product:____________!!!!!!

  37. Protein Synthesis in a Nutshell Replication DNA A A G A C G T A G DNA ______ ______ _______ (transcribe this piece) Transcription mRNA ______ ______ _______ Translation tRNA ______ ______ _______ T T C T G C A T C A A G A C G U A G codons Lys ThrStop Amino Acids U U C U G C A U C anticodon A Protein Finished Product:____________!!!!!!

  38. Transcription

  39. Translation

  40. Protein Synthesis Lab In Pairs… 1. Get a DNA “Code #” from Mrs. M 2. Go to the Nucleus • Write down the DNA strand • Transcribe DNA into an mRNA strand 3. Go to the Ribosome (Rough E.R.) • Write the tRNA anticodons • Flip over anticodon cards to reveal secret message 4. Show Mrs. M • Get a new code Goal: At least 5 proteins synthesized (front of one side complete) Each extra= EXTRA CREDIT

  41. Explain the connection between a codon and an amino acid. Compare the process of translation to translating Spanish into English. Compare Start and Stop codons to the beginning and end of a sentence. 4. What is an anticodon? For # 1-10- use the amino acid chart on pg. 244 to find which amino acids would be encoded by the mRNA codes below: GCC AAA AGC UAG AUA AAU GCA CCG UCA AGG Bottom of p.9

  42. Explain the connection between a codon and an amino acid. A codon is a three-nucleotide sequence that codes for an amino acid. Compare the process of translation to translating Spanish into English. Just as we could translate English into Spanish, cells can translate an RNA message into amino acids, to build proteins. Compare Start and Stop codons to the beginning and end of a sentence. A start codon (like the first word in a sentence) codes for the start of translation and the start of an amino acid chain, the stop codon codes for the end of the amino acid chain (like the period at the end of a sentence). What is an anticodon? A set of three nucleotides that is complementary to an mRNA codon. GCC- alanine AAA- Lysine AGC- Serine UAG- stop codon AUA- Isoleucine AAU- Asparagine GCA- Alanine CCG- Proline UCA- Serine AGG- Arginine

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