https://padlet.com/1018704/qck81kw41dtt en-us 2018-04-10 15:52:29 UTC 2018-04-10 16:25:18 UTC hello@padlet.com 1018704 https://padlet.com/1018704/qck81kw41dtt/wish/250345395 Fredrich Miescher was the first person to identify DNA as a distinct molecule. Miescher isolated "nuclein," DNA with associated proteins, from cell nuclei. His work is important to us because without his discovery we would still think that DNA is an obscure molecule with presumed accessory or structural functions inside the nucleus. ]]> 2018-04-10 15:55:57 UTC https://padlet.com/1018704/qck81kw41dtt/wish/250345395 1018704 https://padlet.com/1018704/qck81kw41dtt/wish/250350689 Rosalind Franklin was able to get two sets of high-resolution photos of crystallized DNA fibers. She used two different fibers of DNA, one more highly hydrated than the other. From this she was able to see the basic dimensions of DNA strands, and that the phosphates were on the outside of what was probably a helical structure. Without her contribution to DNA, we would not even know what the shape of the DNA molecule would look like. ]]> 2018-04-10 16:04:57 UTC https://padlet.com/1018704/qck81kw41dtt/wish/250350689 1018704 https://padlet.com/1018704/qck81kw41dtt/wish/250354110 Watson and Crick worked together as a team and studied the structure of DNA. In April 1953, they published the news of their discovery, a molecular structure of DNA based on all its known features - the double helix. Their model served to explain how DNA replicates and how hereditary information is coded on it. This discovery set the stage for the rapid advances in molecular biology that continue to this day.]]> 2018-04-10 16:11:37 UTC https://padlet.com/1018704/qck81kw41dtt/wish/250354110 1018704 https://padlet.com/1018704/qck81kw41dtt/wish/250355954 DNA is made up of molecules called nucleotides. The four types of nitrogen bases are adenine (A), thymine (T), guanine (G) and cytosine (C). The order of these bases is what determines DNA's instructions, or genetic code. The shape of the DNA structure is a double helix.]]> 2018-04-10 16:14:57 UTC https://padlet.com/1018704/qck81kw41dtt/wish/250355954 1018704 https://padlet.com/1018704/qck81kw41dtt/wish/250356698 The nucleotides of DNA are the basic building block of DNA.
The three parts of the nucleotides are a nitrogenous base, pentose sugar, and a phosphate group. ]]> 2018-04-10 16:16:29 UTC https://padlet.com/1018704/qck81kw41dtt/wish/250356698 1018704 https://padlet.com/1018704/qck81kw41dtt/wish/250359130 Attached to each sugar ring is a nucleotide base, one of the four bases Adenine (A), Guanine (G), Cytosine (C), and Thymine (T). The first two (A, G) are examples of a   purine which contains a six atom ring and five atom ring sharing two atoms. The second two (C, T) are examples of a pyrimidine which is composed of a single six atom ring. A base pair is one of the pairs A-T or C-G. The nucleotides in a base pair are   complementary which means their shape allows them to bond together with hydrogen bonds. The A-T pair forms two hydrogen bonds. The C-G pair forms three. The hydrogen bonding between complementary bases holds the two strands of DNA together. Hydrogen bonds are not chemical bonds. This permits the DNA strands to separate for transcription (copying DNA to RNA) and replication (copying DNA to DNA). ]]> 2018-04-10 16:21:14 UTC https://padlet.com/1018704/qck81kw41dtt/wish/250359130