DNA Structure Notes PDF
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These notes provide an overview of DNA structure, covering the basics and key concepts. They detail the components of DNA, explaining in detail base pairing rules, as well as the discoveries by key scientists such as Watson and Crick. The notes are suitable for high school biology.
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NOTES: DNA Structure What is DNA? - DNA is a molecule containing genetic information. DeoxyriboNucleic Acid - Found in ALL living things - plants/animals/fungi/bacteria - DNA is made of a long ch...
NOTES: DNA Structure What is DNA? - DNA is a molecule containing genetic information. DeoxyriboNucleic Acid - Found in ALL living things - plants/animals/fungi/bacteria - DNA is made of a long chain of nucleotides. Which is a monomer? or Polymer monomer What is a Nucleotide? ➔ DNA (polymer) is made up of a long chain of nucleotides (monomers). ➔ Each nucleotide has three parts. – a phosphate group – a deoxyribose sugar – a nitrogen-containing base A Nitrogen-Containing Base ➔ Each nucleotide contains one of four “nitrogenous bases” ◆ Adenine ◆ Thymine ◆ Cytosine ◆ Guanine Discovering DNA ➔ Watson and Crick determined the 3D structure of DNA by building models. ➔ They are credited with discovering that: ◆ DNA is a double helix with a sugar-phosphate backbone on the outside and bases on the inside. Discovering DNA ➔ Watson and Crick’s discovery built on the work of Rosalind Franklin and Erwin Chargaff. ◆ Franklin’s x-ray images: suggested that DNA was a double helix of even width. ◆ Chargaff’s rules: stated that A=T and C=G. Nucleotides always pair the same way ➔ The base-pairing rules show how nucleotides always pair up in DNA. ➔ Base-Pairing Rules: ◆ A pairs with T ◆ C pairs with G
