DNA

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DNA
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Deoxyribonucleic Acid

• Primarily in nucleus
• Contains the code for making proteins
• Cant get out of the nucleus
• Very large molecule
• Made of nucleotides

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Nucleotides

• Each nucleotide consists of
• one sugar (deoxyribose)
• One phosphate
• One nitrogen base

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Nitrogen Bases

• Adenine
• Thymine
• Guanine
• Cytosine

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Hydrogen Bonds
DALLEN

• Adenine and Thymine have 2
• Guanine and Cytosine have 3

A T C G
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Nucleotides Connected
4 nucleotides are attached here
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The Double Helix
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How does DNA fit into a cell?
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Discoverers of DNA Structure

• James Watson and Francis Crick

• Co-discoverers Rosalind Franklin and M.H.F.
  Wilkins
• Nobel Prize in 1953 (except Franklin, who had
  died)

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DNA Replicates

• Replication makes a copy of itself
• Occurs just before cell division
• Necessary so that each new cell gets a copy of
  the parent cells DNA
• Occurs in nucleus during interphase

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DNA Zipper
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(No Transcript)
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Replication Steps

• H-bonds between N-bases break.
• This causes the molecule to unzip.
• Unattached N-bases attract their complementary
  base.
• Adenine Thymine (T-A or A-T)
• Cytosine Guanine (G-C or C-G)
• New strands are formed each has the same number
  and order of bases.

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DNA Replication in Action
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New DNA Strands are Identical
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DNA is now copied so mitosis or meiosis can take
place.
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The End