Biochemistry

Matrix (M-RNA) is synthesized in the nucleus and is present both in the nucleus and in the cytoplasm. It makes up 4-10% of the RNA of the cell. The molecular weight of M-RNA ranges from 3 * 10 5 to 2 x 10 6 Da. This type of RNA contains four nitrogenous bases: adenine, guanine, cytosine and uracil. M-RNA plays the role of a link between nuclear DNA and ribosomes; it transfers genetic information from DNA to the synthesized polypeptide chain of a protein. Enzymatic way is the "rewriting" of information with chromosomal DNA. After receiving the information, M-RNA passes to ribosomes and becomes a matrix for protein synthesis. The synthesis of each protein in the cell is provided by specific M-RNA. Ribosomal (R-RNA) in the cell is closely associated with ribosome proteins, forming ribonucleoproteins. It accounts for 75 - 80% of the total RNA of the cell. The molecular weight of R-RNA is from 5 x 10 5 to 1.2 x Ю 6 Da. Transport (T-RNA) is located mainly in the cytoplasm that it makes up 10- 15 % of the RNA of the cell. The molecular weight of T-RNA is from 1.8 x 10 4 to 3.5 x 10 4 Da. Along with adenine, guanine, uracil and cytosine, T-RNA contains a certain number of so-called minor bases. The function of T-RNA is to deliver certain amino acids to the ribosomes. Each amino acid has its own special T-RNA. The main characteristics of nucleic acids are presented in table 5.1. Table 5.1 - The main characteristics of nucleic acids Form of nucleleic acids Main location place Function Molecular weight, Da Compound components Form carbohydrate nitrogenous base DNA Nucleus Carrier investigative information Millions Deoxyribose Adenine (A) Guanine (G) Cytosine (9 Timin (T) Double helix I-RNA (informationational) The nucleus and cytoplasm Transfer of informations by DNA Varies Ribose A, G, C, U Linear R-RNA (ribosomal) Cytoplasm Place of transformation of info with I- RNA Highpolymers (10 5 - 10 6 ) Ribose A, G, C, U Contain spherical particles T-RNA (transporting) Cytoplasm Transport of amino acids to the place of protein synthesis 2500 Ribose A, G, C, U Spiral form 121