Nucleic Acids Class Notes Detailed.

Nucleic AcidThe central dogma of molecular biology states that DNA is transcribed to RNA and that is translated to proteins. All cells in a person have the same DNA molecules but different cell types make different proteins. The specialization of cells is called differentiation and happens due to gene expression. For example, an RBC will express the hemoglobin gene whereas a skin cell will not although the gene is present in its DNA, it just isn’t expressed. DNA and RNA are linear polymers of nucleotides. Nucleotides are building blocks of DNA and RNA, each nucleotide has a pentose sugar, a nitrogenous base, and a phosphate group. An oxygen is missing on the 2nd carbon in DNA hence the name “deoxy” whereas the oxygen is present in RNA. There are 5 nitrogenous bases, adenine, thymine, guanine, cytosine and uracil.In DNA adenine, thymine, guanine and cytosine are the 4 bases present whereas in RNA thymine is replaced with uracil. Adenine and guanine fall under the category of “purines”, due to its double ringed structure. Pneumonic – “Pure As Gold”. Cytosine, thymine and uracil fall