Deoxyribonucleic acid initiated

The initial conversion of light into chemical energy takes place in the thylakoid membrane. Besides the chlorophylls and series of electron carriers, the thylakoid membrane also contains the enzyme adenosine triphosphate (ATP) synthase. The enzymes that are responsible for the actual fixation of C02 and the synthesis of carbohydrate reside in the stroma that surround the thylakoid membrane. The stroma also contains deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and ribosomes that are essential for protein synthesis [37]. 

A snbstantial body of experimental evidence indicates that the formation of a covalent bond between chemical carcinogens and cellnlar macromolecnles represents the first critical step in the multistage process, eventually leading to tumor formation (see Geacintov et al. 1997, references therein). Most chemical carcinogens are not active on their own, but require metabolic activation to produce reactive intermediates capable of binding covalently with target macromolecnles, particularly with deoxyribonucleic acid (DNA), and thereby, initiate cancer. 

The results of incorporation experiments using tritiated thymidine lend support to the hypothesis that thymidine rhamnosyl pyrophosphate in Lactobacillus acidophilus is an intermediate on the pathway to deoxyribonucleic acid synthesis. When cells were grown in a medium containing tritiated thymidine, labeled thymidine rhamnosyl pyrophosphate constituted two-thirds of the total label in the acid-soluble fraction. When these cells were transferred to a medium containing 2-deoxyadenosine, 2-deoxy-guanosine, and 2-deoxycytidine as the nucleosides, 99 % of the label initially present was transferred to deoxyribonucleic acid after incubation for 50 minutes. Therefore, almost complete incorporation (into deoxyribonucleic acids) of the isotope from tritiated th3anidine had occurred. 

Uracil was first isolated from herring sperm in 1900 and it originates from ribonucleic acids hydrolytic breakdown gives initially the nucleotide which is further cleaved to uridine (1- -D-ribofuranosidouracil) and finally to uracil. Thymine was originally isolated in 1893 from hydrol-yzates of bovine thymus or spleen. It is one of the four bases in deoxyribonucleic acids which on hydrolysis give thymine via thymidine [3-(2 -deoxy-D-ribofuranosido)-thymine]. 

More than 90 percent of commercial phosphorus production is in the form of calcium salts of phosphoric acid, H3PO4, used as fertilizers. Other significant uses of phosphorus compounds are in the manufacture of matches (phosphorus sulfides), food products and beverages (purified phosphoric acid and its salts), detergents (sodium polyphosphates), plasticizers for polymers (esters of phosphoric acid), and pesticides (derivatives of phosphoric acid). Related to the phosphorus pesticides are nerve gases, poisonons com-potmds that rapidly attack the central nervous system, initially developed during World War II. see also Deoxyribonucleic Acid (DNA) Fertilizer Pesticides. 

Deoxyribonucleic acid Nicotiana tabacum clone NelF-4A6 protein formation initiation factor elF 4A messenger RNA complementary plus 5 - and 3 -flanking region fragment) 950b, 2878c, 4249... 

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