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Science Log: DNA Bubble Map
Pg. 23 in your science log section
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DNA Structure: What does DNA look like?
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What are genes? Passed from one generation to the next (determine inherited characteristics, such as eye color) Found on chromosomes (which are made of DNA) Contain the information to: Build and maintain cell parts Be copied each time a cell divides (The Cell Cycle)
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DNA’s parts DNA is made of NUCLEOTIDES Each nucleotide has: Sugar
Phosphate Base containing nitrogen
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4 types of bases There are 4 types of bases
Adenine Thymine Guanine Cytosine In the 1950s, Chargaff discovered that the amount of A and T are equal and G and C are equal. (Chargaff’s Rules)
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Rosalind Franklin British scientist who used x-ray images to determine the spiral shape of DNA
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Watson and Crick’s Model
Watson and Crick studied the work of Chargaff and Franklin to determine the structure of DNA Figured that it is a “double helix”: Twisted ladder
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How does DNA replicate? Replicate = copy
Watson and Crick also figured out how DNA replicates! Steps to replicate: “Double Helix” unwinds Ladder unzips New nucleotides come in to make two new strands
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Steps to replicate: 1. “Double Helix” unwinds and unzips
Enzyme (chemical) called helicase does this
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Next, the exposed bases on each strand find new nucleotide partners
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The end result!
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