The Functions of ATPATP plays a very important role in a living cell. It drives different cellular processes such as synthesis of new chemical compounds, membrane transport, mechanical work and many more. Read more: http://www.brighthub.com/science/medical/articles/16096.aspx#ixzz1EkeZFJbv Adenosine Triphosphate, commonly known as ATP, is highly important in all biochemical processes. Without this energy rich compound, cellular metabolism would be so impossible. It is the principal energy source of the cell. The ATP supplies of the cell are usually produced in the mitochondria through the process of oxidative phosphorylation. Cellular activities that need energy spending fall into three common categories, and two rarer ones: Synthesis of New Chemical Compounds The endoplasmic reticulum needs ATP to synthesize different important proteins like enzymes which facilitate fast chemical reactions. All cells employ ATP for this general purpose. Some cells, especially cells with high rate of secretion (e.g. salivary and digestive gland cells) and cells in the growth stage (e.g. developing germ cells), use up to 75% of the ATP they generate just to manufacture new chemical compounds (Lehninger 2005). Membrane Transport The selective transport of nutrient and mineral molecules across the digestive tract wall requires ATP. Scientists think all cells employ ATP for at least some forms of transport. This can arrive at extremes in specialized transporters such as kidney tubules, which can use up as much as 80% of their ATP currency (Lehninger 2005) to operate their selective membrane transport mechanisms. Mechanical Work ATP is needed for the contraction of skeletal and cardiac muscles. The heart must contract in order to pump blood toward the different parts of the body. The skeletal muscles should also contract in order for us to do different physical activities such as lifting an object. These activities entail great amount of ATP. Bioluminescence ATP reacts with large carbon-nitrogen molecules (a luciferin) to produce photons in the visible range of wavelength. This use of ATP is somewhat rare on land, but is common in marine organisms, especially in the deep. large amount of ATP are manufactured.brighthub. • The nitrogen base is represented by compounds having nitrogen and carbon in the ring structure.Heat Production ATP is generally used for the purposes of thermoregulation and other uses of high temperature. and phosphorous. • • The phosphate group is represented by phosphoric acid (H3PO4). A nucleotide is a compound containing carbon. It is represented by either ribose sugar (C5H10O5) or deoxyribose sugar (C5H10O4). glycolysis does provide at least some ATP under anaerobic conditions. Principles of Biochemistry. A single ADP/ATP molecule may transfer back and forth between the mitochondria and cytosol for this recharging/expenditure cycle thousands of times per day. A molecule of a nucleotide is in turn composed of three smaller molecules phosphate (P) sugar (S) and nitrogen base (N). These energy-diminished ADP molecules enter the mitochondria for “recharging” and then the cycle back into the cytosol as energy-rich ATP molecules after participating oxidative phosphorylation. Albert. Two types of nitrogen bases occur. Skeletal muscles and special heater tissues convert chemical-bond energy into heat. New York : W. which contain the metabolic machinery for oxidative phosphorylation. nitrogen. Reference Lehninger. 2005. which form the monomers of nucleic acids that are involved in the information transfer system of the cells. which have a double ring structure and b) Pyrimidines. If it were not for the mitochondria. As a consequence of cellular energy spending to support these different activities. They are also involved in the mechanism of energy transfer in cells. This occurs for useful purposes only in a few groups of organisms. Freeman Read more: http://www. namely a) Purines.aspx#ixzz1Ekeln27c Nucleotides are nitrogen containing organic compounds. oxygen.H. hydrogen. . Both the sugars have a furanose ring structure. The high demands for ATP provide glycolysis alone an inadequate as well as ineffective supplier of power for most cells. the energy capability of a cell would be very limited. However.com/science/medical/articles/16096. which have a single ring structure. The sugar molecule in the nucleotide is a 5-carbon pentose sugar. 14 . A combination of nitrogen base with sugar is called as a nucleoside. . Nucleosides involving ribose sugars are called ribonucleosides. fig. and Uracil (U). 13. Similarly.Structures of Nitrogenous Bases in Nucleic Acids The nitrogen base molecule is attached to the sugar molecule by a glycosidic bond. Pyrimidines are of three types Cytosine (C). Thymine (T). nucleosides involving deoxyribose sugars are called deoxy ribonucleosides.15 . 13.fig.Components of Nucleic Acids Purines are of two types adenine (A) and guanine (G). They form the monomers of ribose nucleic acid (RNA). FAD-Flavin Adenine Dinucleotide. Linkage of additional phosphate group occurs at the cost of a large amount of energy. Hence. For example.Formation of a Nucleotide The nucleotides which form nucleic acids have only one phosphate group (monophosphates).Adenosine Triphosphate (ATP) Similarly. Nucleotides formed by ribonucleosides are called ribonucleotides. these higher nucleotides (with one or two additional phosphates) form energy rich compounds. They form the monomers of deoxyribose nucleic acid (DNA). Adenine + Pentose Sugar . . Nucleotides formed by deoxyribonucleosides are called deoxyribonucleotides.6 . Each of them can form a diphosphate and a triphosphate.A nucleoside combines with a phosphate group to form a compound called nucleotide.Adenosine (Adenine Nucleoside) Adenosine + Phosphate . The bonds that join the additional phosphate groups are called as high energy or energy rich bonds. fig.Adenylic Acid or Adenosine Mono Phosphate (AMP)(Adenine Nucleotide) Adenosine Monophosphate + Phosphate . for other nitrogen bases. Separation of these additional phosphate groups from the nucleotides by enzymatic hydrolysis releases correspondingly large amount of energy. 13.Adenosine Diphosphate(ADP) Adenosine Diphosphate + Phosphate . NAD Nicotinamide Adenine Dinucleotide. The nucleotides by combining with other organic compounds or molecules form co-enzymes. .Some nucleotides like cyclic AMP function as regulatory chemicals controlling diverse cellular functions.