Energy160-page6 - form of the nucleotide, ATP. Cells do not...

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Energy Flow in Cells - 6 Applying Energy Flow to Coupled Reactions Keeping cells alive takes work and requires energy. This energy comes from exergonic reactions within the cells that provide the free energy to perform the endergonic reactions needed to keep cells and tissues functioning. We refer to these paired reactions as coupled reactions. For example, the release of energy from the oxidation of glucose fuel molecules, for example, is coupled to the endergonic assembly of proteins and other macromolecules in cells and tissues. By far, the most common energy coupler in chemical reactions is the nucleotide, ATP. Speaking of ATP For some reason, in order for energy to be useful to do cell work, it must be in the
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Unformatted text preview: form of the nucleotide, ATP. Cells do not directly use other forms of energy, so that the energy of chemical fuel molecules must be transformed into ATP before cell work can be done. ATP is then used to provide the energy to complete an endergonic chemical reaction. ATP has three "high-energy" phosphate bonds. The second and third phosphate bonds of ATP are unstable. When this phosphate bond is broken by hydrolysis, energy is released (an exergonic reaction). This released energy is just perfect for the amount of energy needed for many cell reactions. This is why we call ATP an energy carrier. It “carries” the energy needed to do the cell work....
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This note was uploaded on 12/29/2011 for the course BIO 151 taught by Professor Edwards during the Spring '10 term at SUNY Stony Brook.

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