DNA and RNA intro and experiments
What is DNA? DNA is a polymer of four types of nucleotides. Each nucleotide has a deoxyribose sugar, three phosphate groups, and a nitrogen-containing base. The nitrogen containing base is what the DNA is named after. The following are the names of the nitrogen containing bases: adenine (A), guanine (G), thymine (T), and cytosine (C). DNA structure : A DNA molecule has two chains (strands) of nucleotides running in opposite directions and coiled into a double helix. Covalent bonds link the deoxyribose (sugar) of one nucleotide to a phosphate group of the next, forming the sugar–phosphate backbone of each chain. Hydrogen bonds between the internally positioned nitrogenous bases hold the two strands together. Chargaff’s first rule : First, the amounts of thymine and adenine are identical in any DNA molecule, as are the amounts of cytosine and guanine (A = T and G = C). We call this discovery Chargaff ’s first rule Experiments with DNA : Griffith - F irst experiment sho...