Adenosine Triphosphate - Chem
INTRODUCTION Adenosine triphosphate is the source of about 95% of the body's energy requirements. The body burns food, storing some of the energy in the bonds of ATP. When these bonds are broken the energy is released supplying the body with energy for other reactions. ATP is simultaneously an ester, an alkanoic acid and an anhydride. ATP has a chemical formula of C10H16N5O13P3 and a CAS number of 56-65-5. Its molecular weight is 507.19. ATP is a nucleotide, a small organic molecule with three major components. A five-carbon sugar (ribose), adenine - a nitrogen-containing compound that is also one of the bases of DNA and RNA, and three phosphate units each composed of a phosphorous atom and four oxygen atoms. PROPERTIES The most important property of ATP is obviously its ability to function as an energy carrier. Energy is stored in the covalent bonds between the phosphates (shown as ~ in Diagram 1). When the third phosphate group is removed by hydrolysis, ATP + H2O _ ADP + P + energy ADP is adenosine diphosphate, which has one less phosphate unit than ATP. P is an inorganic phosphorous atom that is usually transferred to the molecule where the energy is required in a process known as phosphorylation. This reaction produces a sub
stantial amount of energy, the amount varies depending upon conditions, but under normal cell condition 7.3Kcal/mol is produced. The effect of pH is one way in which the amount of energy produced changes. Under acidic conditions more protons are available which reduces the negative charge of the ATP, lowering the amount of energy produced. E.g. at pH 4 E= -6.4 kcal at pH 7 E= -7.3 kcal at pH 9 E= -9.8 kcal. ATP is an endergonic molecule; this means that it requires energy to be formed. The phosphate bonds of ATP are remarkable structures. The formation of these bonds requires a larger than normal input of energy. This is due to two reasons 1) electrostatic repulsion of negatively charged oxygen atoms in close proximity and 2) resonance stabilization of electrons in the triphosphate component. Resonance allows electrons to spread out the energy load, so extra energy is required to stabilize ATP. The main reason ATP is employed for energy transfers is the fact that it is a comparatively large, charged molecule. This prevents it form passing through membranes and thus it cannot "escape" into or out of organelles and cells. An electronegative field surrounds solvated ATP. This is because oxygen is more electronegative than phosphorous, giving the oxygen molecule a slight negative charge. (Refer to diagram 2). The slight negative charge of the ATP molecule makes it soluble in water. This property is also partially due to the ribose component, which lowers the free energy of surrounding water molecules. The adenine component of ATP offers anti-oxidation protection to the molecule, which is essential for the molecule to survive for long periods of time
Some common words found in the essay are:
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Approximate Word count = 1117
Approximate Pages = 4 (250 words per page double spaced)
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