Chap. 10 : Nucleic Acids

1
Chap. 10 Nucleic Acids Protein
Synthesis

• DNA deoxyribonucleic acid
• - function store and use information to
  direct activities of the cell and to make exact
  copies of itself.

2
- made up of repeating subunits called
nucleotides

• A. Nucleotide
• - made up of 3 parts
• 1. 5 carbon sugar called deoxyribose
• 2. phosphate group (PO)
• 3. nitrogen base what causes DNA to
• vary in all living things.

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-- 4 different bases

• 1. adenine (A)
• 2. guanine (G)
• 3. thymine (T)
• 4 cytosine (C)
• B. Double Helix
• - nucleotides bond together to form strands.
  2 strands bond together in the shape of a spiral
  twist called a double helix. Discovered by Watson
  and Crick (1953)

Called purines (double rings)
Called pyrimidines (single rings )
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Structure of DNA
Purine base
Pyrimidine base
H
H
Sides made up of a sugar and phosphate. Held
together by a covalent bond.
H
Sides joined together by weak hydrogen bonds
5
Called complementary strands because

• Adenine always bonds with Thymine (AT)
• Cytosine always bonds with Guanine (CG)
• A-T-G-G-C-C-A-A-C-G-T-A
• T-A-C-C-G-G-T-T-G-C-A-T