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DNA and Protein Synthesis

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					DNA and Protein Synthesis
                      DNA and RNA
• DNA
  –   Double Helix
  –   Pentose sugar (deoxyribose)
  –   Phosphate
  –   Nitrogenous bases
        • Purines: double ringed
             – Adenine and guanine
        • Pyrimidines: single ring
             – Thymine and cytosine
  – Nucleotide: sugar, phosphate, and one base
  – Functions: ability to copy itself and protein synthesis
• RNA
  –   Ribose
  –   Uracil instead of thymine
  –   Single stranded
  –   tRNA, mRNA, rRNA
          Protein Synthesis
• Transcription: process in the nucleus by
  which DNA serves as a template for
  mRNA
• Translation: process in the cytoplasm by
  which mRNA is converted into a protein
          Steps of Protein Synthesis
1.       DNA unzips itself
     •      Antisense strand: used to make mRNA
     •      Sense strand: same as mRNA
2.       Heterogenous nuclear RNA is made in the nucleus and the
         introns are spliced out.
3.       mRNA leaves the nucleus and attaches to the smaller subunit of
         the ribosome
4.       tRNA brings one amino acid at a time to the ribosome and
         attaches by the anticodon
5.       Larger subunit of the ribosome attaches containing three tRNA
         binding sites
     1.     A site: holds the next amino acid
     2.     P site: holds the polypeptide
     3.     E site: holds the tRNA to leave the ribosome
6.       Ribosome moves to the next codon until it reaches the stop codon
7.       Start codon: AUG Stop codons: UAA, UAG, UGA

				
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posted:4/6/2013
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