Ribonucleic acids cellular functions

The nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), are the chemical carriers of a cell s genetic information. Coded in a cell s DNA is the information that determines the nature of the cell, controls the cell s growth and division, and directs biosynthesis of the enzymes and other proteins required for cellular functions. 

All corticosteroids have the same general mechanism of action they traverse cell membranes and bind to a specific cytoplasmic receptor. The steroid-receptor complex translocates to the cell nucleus, where it attaches to nuclear binding sites and initiates synthesis of messenger ribonucleic acid (mRNA). The novel proteins that are formed may exert a variety of effects on cellular functions. The precise mechanisms whereby the corticosteroids exert their therapeutic benefit in asthma remain unclear, although the benefit is likely to be due to several actions rather than one specific action and is related to their ability to inhibit inflammatory processes. At the molecular level, corticosteroids regulate the transcription of a number of genes, including those for several cytokines. 

It is possible that in the future we may recognize Kossel s idea of the anlage, a basic protein determiner found in all cells, to be the modern-day equivalent of the coat or masking protein which actually determines the particular areas of the DNA (deoxyribonucleic acid) molecule which are to function in RNA (ribonucleic acid) formation in a given cell—that is, Kossel s anlage may be the intellectual antecedent of the principle of cellular differentiation as viewed by many today. On the other hand, if such kindness to our predecessors is to be extended to the ideas of Richard Block, who transformed KossePs anlage first to the basic amino acids (7) and then to common peptides, it can easily be said that the concept of the common active site sequence of many enzymes (20) is what Block meant when he inferred that a peptide anlage determined the function of many proteins. 

Ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) are both biopolymers of nucleic acids, but they have minor structural differences that lead to major functional differences. All living cells use DNA as the primary genetic material that is passed from one generation to another. DNA directs and controls the synthesis of RNA, which serves as a short-lived copy of part of the much larger DNA molecule. Then, the cellular machinery translates the nucleotide sequence of the RNA molecule into a sequence of amino acids needed to make a protein. 

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The functional modulation of the effect of cytokines requires the presence of cellular and soluble receptors. The expression of these receptors is regulated by specific signals, often dependent on cytokine networks. Transiently produced and of short half-life, cytokines are typically not stored as preformed molecules, and their production is dependent on transient genetic transcriptional activation and short-lived messenger ribonucleic acid (mRNA). Cytokines are rapidly secreted, leading to a brief burst of cytokine release. This burst is very important for cytokines to achieve distant activities, contrasting with the small amount of these molecules necessary for local functions (see later section on interleukin-1). 

There are two types of nucleic acids—deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA encodes an organism s hereditary information and controls the growth and division of cells. In most organisms the genetic information stored in DNA is transcribed into RNA. This information can then be translated for the synthesis of all the proteins needed for cellular stracture and function. 

In cellular biological organisms nearly all chemical reactions are catalyzed by enzymes. For example, the enzyme urease catalyzes the hydrolysis of urea and the enzyme protease catalyzes the hydrolysis of proteins. Most enzymes are proteins, although some ribonucleic acids have been found to exhibit catalytic activity and have been called ribozymes. Ribozymes usually catalyze the combination of other RNA fragments, and require the presence of divalent metal ions such as Mg +. It has been thought that divalent metal ions were necessary to the function of ribozymes, but... 

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