Ribonucleic acid ribosomal rRNA

The chemical polymerization of even a moderately sized protein of a hundred amino acids in the laboratory is extremely laborious, and the yields of active product can often be low to zero (Kent and Parker, 1988). Cells accomplish this task by using an intricate mechanism which involves catalytic machinery composed of proteins, nucleic acids and their complexes, and synthesize polypeptide chains that are composed of hundreds of amino acids. This process is depicted in Fig. 2.4, and is described in the sections below. The basic components of the cellular protein synthesis apparatus, in all known biological systems, are ribosomes, which are aggregate structures containing over fifty distinct proteins, and three distinct molecules of nucleic acid known as ribosomal ribonucleic acid (ribosomal RNA or rRNA). The amino acids are brought to the ribosomes, the assembly bench , by an RNA molecule known appropriately as transfer RNA . Each of the twenty amino acids is specifically coupled to a set of transfer RNAs (discussed below) which catalyze their incorporation into appropriate locations in the linear sequence of polypeptide chains. Several other intracellular proteins known as init iation and elongation factors a re also required for protein synthesis. 

NAD Oxidized nicotinamide adenine rRNA Ribosomal ribonucleic acid... 

The nucleus stores the cell s genetic information as DNA in chromosomes. It is bounded by a double membrane but pores in this membrane allow molecules to move in and out of the nucleus. The nucleolus within the nucleus is the site of ribosomal ribonucleic acid (rRNA) synthesis. 

Deoxyribonucleic acid is the genetic material such that the information to make all the functional macromolecules of the cell is preserved in DNA (Sinden, 1994). Ribonucleic acids occur in three functionally different classes messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA) (Simons and Grun-berg-Manago, 1997). Messenger RNA serves to carry the information encoded from DNA to the sites of protein synthesis in the cell where this information is translated into a polypeptide sequence. Ribosomal RNA is the component of ribosome which serves as the site of protein synthesis. Transfer RNA (tRNA) serves as a carrier of amino acid residues for protein synthesis. Amino acids are attached as aminoacyl esters to the 3 -termini of the tRNA to form aminoacyl-tRNA, which is the substrate for protein biosynthesis. 

The nucleus of the cell (Figure 1.2) is composed of a porous nuclear membrane, the nucleolus, and soluble materials. The nucleolus contains ribonucleic acids (RNA) and genetic materials also termed chromatin that code for the proteins synthesized upon the ribosomes in the cell cytoplasm. The nuclear membrane is continuous with the outer membrane of the endoplasmic reticulum. Messenger RNA synthesized in the nucleus is transported across the nuclear membrane and is involved in protein synthesis. It fits into the groove between the large and small rRNA subunits (Figure 1.2)... 

Ribosomal ribonucleic acid (rRNA), 37 RIM (reaction injection molding), 110,162 Ring-opening olefin metathesis... 

Approximately 1000 proteins comprise the mitochondrion the majority are encoded on genes located on nuclear DNA. In fact, as seen in Figure 8-5, the mtDNA encodes only 13 proteins. These mtDNA-encoded proteins are the seven subunits (ND1,2,3,4,4L, 5, and 6) of the NADH-dehydrogenase (RC I) one subunit (cytochrome b) of RC III three subunits (CO I, II, and III) of cytochrome c oxidase (RC IV) and two subunits (A6 and A8) of the ATP synthase (RC V).A11 of these proteins are components of the ETC or the ATP synthase involved in OXPHOS. In addition to these 13 proteincoding genes, the mtDNA encodes 22 mitochondrial transfer ribonucleic acids (tRNAs) and two ribosomal RNA (rRNA) molecules (the large 16S rRNA and the small 12S rRNA). 

RNA ribonucleic acid mRNA messenger RNA rRNA ribosomal RNA scRNA small cytoplasmic RNA snRNA small nuclear RNA tRNA transfer RNA RNAse ribonuclease Ser serine T thymine Thr threonine... 

Rickets, 482,483,575,576, 582,583, 584 Rislt ratio, 908, 965-%6,968 RMR, see Resting iretabolic rate RNA (ribonucleic acid), 12 cellular function, 32 chetnical structure, 13 structure, 937 synthesis, 13,16 RNA polymerase, 33-35 RNasas, 122 Rods, 561,563-564 rRNA (ribosomal RNA), 34 Rubidium, 703... 

In deoxyribonucleic acid (DNA) the carbohydrate is 2-deoxy-D-ribose, while in ribonucleic acid (RNA) the carbohydrate residue is ribose. Three types of RNA were recognized, and they can be messenger RNA (mRNA), transfer RNA (tRNA), or ribosomal RNA (rRNA), which is the most abundant in cells. Values between 10 and 10 Dalton have been reported for the molecular weight of DNA, and the molecular weight is about 10 for rRNA, 10 for mRNA, and lOMor rRNA. The simplified structures of DNA and RNA are the following ... 

RNA (ribonucleic acid) A large linear molecule made up of nucleotides, ribonucleotides which contain the bases uracil, guanine, cytosine and adenine. RNA occurs in several forms, transfer RNA (tRNA), ribosomal RNA (rRNA) and messenger RNA (mRNA). All are concerned with protein synthesis. All cellular RNAs are synthesized by transcription of chromosomal DNA which acts as the template. 

Know the role of ribosomal ribonucleic acid (rRNA). 

The P. falciparum mitochondrion contains 30-100 copies of the genome and encodes only three proteins (cytochrome b and subunits I and III of cytochrome oxidase) and ribosomal ribonucleic acid (rRNA). The rRNA genes are fragmented and scrambled it does not encode any transfer ribonucleic acid (tRNA), ribosomal proteins or ATPase subunits. As such, the Plasmodium mitochondrion denotes an endpoint in the slimming down process whereby the ancient progenitor of all mitochondrial genomes began the slow march to near total dependence on host nuclei (Williamson, 1998). 

The mRNA leaves the nucleus and attaches itself to ribosomal ribonucleic acid (rRNA) in the cytoplasm of the cell. Without going into precise detail, rRNA reads the base-sequence code of mRNA and a third type of RNA, transfer ribonucleic acid (tRNA) brings the correct amino acid to the forming protein. This process is known as translation. Each amino acid is coded for by a sequence of three bases, known as a triplet code. For example, ACA codes for the amino acid cysteine. As amino acids are added in sequence a protein is built up. 

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