1. Protein Synthesis Continued After transcription

2. RNA editing After a strand of RNA is constructed by transcription, it must be altered before it moves to the cytoplasm After a strand of RNA is constructed by transcription, it must be altered before it moves to the cytoplasm Introns are sections of the RNA that do not code for a protein and are “cut out” of the RNA strand (they stay IN the nucleus) Introns are sections of the RNA that do not code for a protein and are “cut out” of the RNA strand (they stay IN the nucleus) Exons are then spliced back together because they code for the protein (they EXIT the nucleus) Exons are then spliced back together because they code for the protein (they EXIT the nucleus)

4. RNA language Remember that RNA codes for a specific order of amino acids to make a protein Remember that RNA codes for a specific order of amino acids to make a protein The RNA strand is read in triplets (threes) called codons The RNA strand is read in triplets (threes) called codons RNA strand = UCGCACGGUU RNA strand = UCGCACGGUU Read as = UCG / CAC / GGU Read as = UCG / CAC / GGU

5. RNA  Proteins Each codon “codes” for a specific amino acid Each codon “codes” for a specific amino acid Using the chart on p. 303 decode the mRNA sequence from the previous slide. Using the chart on p. 303 decode the mRNA sequence from the previous slide. –UCGCACGGUU –Serine – Histidine - Glycine

6. “Special Codons” The amino acid methionine “AUG” is the code for start or GO The amino acid methionine “AUG” is the code for start or GO Notice on the chart on p. 303 that several sequences code for “STOP” Notice on the chart on p. 303 that several sequences code for “STOP” These are used to start or stop protein sythesis These are used to start or stop protein sythesis

7. Using the chart Also notice that more that one codon will code for the same amino acid Also notice that more that one codon will code for the same amino acid –Ex: Arginine has the codons CGU CGU CGC CGC CGA CGA CGG CGG This is called the “wobble effect” so if a mutation occurs it may not effect the amino acid sequence. This is called the “wobble effect” so if a mutation occurs it may not effect the amino acid sequence.

8. Amino Acid Sequencing On page 303, do the “Quick Lab” On page 303, do the “Quick Lab” You may write your answers in your notes, however do your OWN work and I will insure that you have the answers before you can exit the classroom. You may write your answers in your notes, however do your OWN work and I will insure that you have the answers before you can exit the classroom.

9. “Say it With DNA” Project Each amino acid has been assigned a letter Each amino acid has been assigned a letter Create a ONE OF A KIND message using those letters (a sentence with DHS in it would be cool) Create a ONE OF A KIND message using those letters (a sentence with DHS in it would be cool) Figure out the DNA strand, RNA complementary strand, the codons, and the amino acid strand and finally the message Figure out the DNA strand, RNA complementary strand, the codons, and the amino acid strand and finally the message Place the above on your poster Place the above on your poster Decorate the poster as you wish (Hint: double helices make excellent accents) Decorate the poster as you wish (Hint: double helices make excellent accents)