Bio prelab DNA

Bio prelab DNA - Chapter 19 DNA is composed of building...

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Chapter 19 DNA is composed of building blocks called nucleotides consisting of: -A deoxyribose sugar -A phosphate group -One of four nitrogen bases -Adenine (A) -Thymine (T) -Guanine (G) -Cytosine (C) Ratios of A-to-T and G-to-C are constant in all living things -A is always paired with T, and G always with C on the double helix James Watson and Francis Crick published first accurate model of the DNA molecule -Discovered that the order of nucleotides changed, allowing information to be encoded into the DNA sequence -Base pairing is key to DNA’s structure Erwin Chargaff -Isolated DNA from different organisms -Ratios of A to T are very close, as are the Ratios of G to C X-ray patterns (Wilkins) -Diameter of the helix stays the same -Vertical distance between bars: 34 Angstroms -Distance between stacked base pairs: 3.4 Angstroms (10 nucleotides per helical repeat) G makes 3 hydrogen pairs with C A makes 2 hydrogen pairs with T Sugar and phosphate groups on the outside, base pairs inside Chapter 21 RNA is found in cytoplasm
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Bio prelab DNA - Chapter 19 DNA is composed of building...

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