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12-3 RNA & Protein Synthesis

12-3 RNA & Protein Synthesis. Fill-in Notes. Genes are coded DNA instructions that control the production of proteins in the cell. Transcription. Translation. A Molecular Definition of Genes. Ribo nucleic acid Like DNA ( deoxyribo nucleic acid) EXCEPT: 1) 5-carbon sugar is ribose

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12-3 RNA & Protein Synthesis

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  1. 12-3 RNA & Protein Synthesis Fill-in Notes

  2. Genes are coded DNA instructions that control the production of proteins in the cell Transcription Translation A Molecular Definition of Genes

  3. Ribonucleic acid • Like DNA (deoxyribonucleic acid) EXCEPT: • 1) 5-carbon sugar is ribose • 2) Single-stranded • 3) Contains URACIL (U) instead of thymine (T) What is RNA?

  4. Messenger RNA (mRNA) • Serves as “messengers” from DNA to the rest of the cell • Ribosomal RNA (rRNA) • Makes up ribosomes, along with protein • Transfer RNA (tRNA) • Transfer amino acids to the ribosome Types of RNA

  5. TRANSCRIPTION is the copying of a sequence of DNA into a complementary sequence of mRNA • Requires enzyme, RNA polymerase • Binds to and separates DNA strands • Uses strand of DNA as template to assemble mRNA • RNA polymerase binds to promoters, sequences of DNA that signal where to begin transcription Transcription

  6. How would we transcribe this sequence of DNA into mRNA? DNA sequence: GTAAGCTC mRNA sequence: CAUUCGAG

  7. DNA of eukaryotic genes contains sequences called introns, which are NOT involved in coding for proteins • Exons are sequences that code for proteins RNA Editing

  8. Amino acid = smallest part of a polypeptide • Polypeptide = a chain of amino acids. • Protein = a complex structure made of polypeptides Things Found in a Cell

  9. The genetic code is responsible for building all the proteins in the body using 20 different amino acids. • mRNA is the genetic code • 4 RNA bases: U, A, G, C • Each coded “message” is 3 bases long • How many 3 letter words can you make from the letters A,T,G and C? • 4 x 4 x 4 = 64 The Genetic Code

  10. Codons are three letter “words” that specify an amino acid • There are 64 possible codons Example mRNA sequence: UCGCACGGU We would read this as: UCG – CAC – GGU Corresponding amino acids: Serine – Histidine – Glycine Some amino acids are specified by more than one codon, and some codons are “START” and “STOP” signals Codons

  11. 2 different types of amino acid charts…

  12. Which amino acid does AUG stand for? • MET = methionine

  13. Which amino acid does CUC stand for? • LEU = leucine Which amino acid does UGA Stand for? • UGA = Stop

  14. TRANSLATION is the process of decoding the information from mRNA to produce proteins • mRNA =instructions • Ribosomes join the amino acids together as directed by the tRNA • Starts with codon-AUG • Ends with a stop codon Translation

  15. mRNA that has been transcribed from DNA in the nucleus is released to the cytoplasm Step 1

  16. mRNA attaches to the ribosome • As codons move through the ribosomes, tRNA transfers the correct amino acidto the growing polypeptide chain Step 2

  17. Transfers the correct amino acid to the chain • At one end an amino acidis attached • At the other end there is an anticodon that pairs with the mRNA • Occurs at the ribosome tRNA

  18. Anticodons are complementary to the mRNA sequence • Which anticodon would be on the tRNA that would pair with UCG on the mRNA? • AGC

  19. Ribosome forms a bond between the amino acids and releases the used tRNA • Protein grows until the STOP codon is reached • Ribosome then releases the protein and the mRNA Step 3

  20. Genes containinstructionsfor making proteins • Many proteins are enzymes that catalyze and regulate chemical reactions • These proteins can determine an organism’s traits • For example: • Enzymes can determine pigment color of a flower or human blood type Genes & Proteins

  21. Put your answers at the bottom of your notes (they will be returned to you after they are graded) • Open textbook to pg. 303 Quiz Time

  22. 1. Which nitrogenous base replaces thymine (T) in RNA? 2. How many strands are in RNA? 3. How many letters or bases, make up a codon? 4. What gets made during Translation? 5. Which amino acid gets made from the codons U-U-C? Use pg 303 in book. QUIZ

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