Genes are particularregions of DNA (A, T, C, and G nucleotides in a particular order) thatcontain the instructions for making RNA and protein molecules.
Folate coenzymes are responsible for the following important metabolic functions and benefits: 1) Formation of purines and pyrimidines, which in turn are needed for synthesis of the nucleic acids DNA and RNA. This is especially important during fetal development in the first trimester in preventing birth defects, such as neural tube defects, 2) Formation of heme, the iron-containing protein in hemoglobin, 3) Interconversion of the 3-carbon amino acid serine from the 2-carbon amino acid glycine, 4) Formation of the amino acids tyrosine from phenylalanine and glutamic acid from histidine, 5) Formation of the amino acid methionine from homocysteine (Vitamin B12 as also is needed for this conversion). In the reconversion of homocysteine to methionine the body uses the methionine to make the important amino acid s-adenosylmethionine (SAMe) which is known to be helpful in cases of depression, 6) Synthesis of choline from ethanolamine, 7) Formation and maturation of red and white blood cells, and 8) Conversion of nicotinamide to N’-methylnicotinamide.
A. Basic Chemical Structure The basic information for all activities in living systems, at least on our planet, is stored ultimately in nucleic acids, namely, deoxyribonucleic (DNA) and ribonucleic (RNA) acids. Except for certain viruses, DNA is the universal genetic material (Fig. 1). The chemical structures of basic units of RNA and DNA have been […]
It was mentioned on an earlier page that the synthesis of proteins wasdirected by nucleic acids and that DNA was ultimately responsiblefor the sequence of amino acids in those proteins. Let's turn our attention now to thesequence of reactions by which the genetic information in DNA dictates which proteins areformed and what will be their primary structure.
A. Similarity of DNA and RNA Synthesis All nucleic acids are usually synthesized by DNA template-guided polymerization of nucleotides—ribonucleotides for RNA and deoxy(ribo)nucleotides for DNA. The reactant monomers are 5′ ribonucleoside (or deoxyri-bonucleoside) triphosphates. These can be described in the following chemical equations: and Enzymatic polymerization is carried out by DNA and RNA polymerases, both […]
tRNA binds to mRNA by complementary base-pairing,so tRNA also serves as a "bridge" between the information code of DNA andRNA (the order of the nucleotides) and the code of protein (the order ofamino acids).
Development of strategies for chemical synthesis of nucleic acids represented a major breakthrough in molecular biology, because most of the current approaches involving PCR, manipulation of recombinant DNA, studies of gene regulation, etc. require synthetic DNA and RNA oligonu-cleotides with defined sequences. The difficulty of synthesizing RNA and DNA polynucleotide chains from mononucleotide units lies […]