Biochemistry

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Biochemistry

• Nucleic Acids

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Nucleic Acids

• Composition Made up of nucleotides which each
  consist of three parts - a sugar, a base, and a
  phosphate group
• Structure polynucleotides which consist of a
  base attached to a backbone of sugar and
  phosphate
• Function provide information the cell uses to
  assemble protein molecules

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Tro, 415
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Components of Nucleic Acids

• The phosphate is from phosphoric acid, H3PO4
• The sugars are either 2-deoxyribose or ribose
• The bases are purines (adenine and guanine) or
  pyrimidines (cytosine, thymine, and uracil)

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Sugar Components of Nucleic Acids
Hill/Kolb, "Chemistry for Changing Times",
7th,Prentice Hall, NJ, 1995, 473.
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Base Components of Nucleic Acids
Hill/Kolb, "Chemistry for Changing Times",
7th,Prentice Hall, NJ, 1995, 473.
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Base Components of Nucleic Acids
Hill/Kolb, "Chemistry for Changing Times",
7th,Prentice Hall, NJ, 1995, 473.
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A Nucleotide
A Nucleotide
Hill/Kolb, "Chemistry for Changing Times",
7th,Prentice Hall, NJ, 1995, 473.
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Nucleic Acid polynucleotide Backbone
chain of deoxyribose and phosphate groups. Bases
(attached to same side of backbone) are
DNA
Phosphate links C-5 of one sugar to C-3 of next
sugar
A Adenine T Thymine G Guanine C Cytosine
Brady/Holum, Fundamentals of Chemistry, 3rd,
Wiley, NY, 1988, 1039.
RNA has OH at C-2
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Base Pairing in DNA
Hydrogen bonds (dotted lines) can form between
bases on parallel nucleic acid chains
Brady/Holum, Fundamentals of Chemistry, 3rd,
Wiley, NY, 1988, 1041.
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DNA Double Helix
Hydrogen bonds that hold the two strands together
are indicated by dotted lines.
Brady/Holum, Fundamentals of Chemistry, 3rd,
Wiley, NY, 1988, 1040.
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Function of Nucleic Acids

• The blueprint for making proteins occurs in the
  base sequence of the double helix of DNA
• Three bases compose one codon that specifies one
  amino acid
• A portion of DNA that contains the sequence of
  codons that specify a single protein is called a
  gene

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Hill/Kolb, "Chemistry for Changing Times",
8th,Prentice Hall, NJ, 1998, 415.