Energy160-page5

Energy160-page5 - randomly However the rate of a chemical reaction at normal earth temperatures may be so slow that it is imperceptible No matter

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Energy Flow in Cells - 5 Endergonic Chemical Reactions Some chemical reactions require or consume energy -- the amount of energy in the products is more than that of the reactants. Such reactions are said to be endergonic. The dehydration synthesis that forms the peptide bond between amino acids is an example of an endergonic chemical reaction. Endergonic Reactions of Photosynthesis Activation Energy Given enough time, an exergonic reaction can (and will) occur spontaneously. Endergonic reactions require energy from some other source in order to take place. In living organisms the source of this needed energy is usually ATP, a molecule we will discuss in a few minutes. For any chemical reaction to get started, the reactants must come together at the right bonding place at the right time. Remember that all atoms and molecules are in motion, so at some time, it is possible that the reactants will come together
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Unformatted text preview: randomly. However, the rate of a chemical reaction at normal earth temperatures may be so slow that it is imperceptible. No matter how energetically favorable a chemical reaction is, some energy is needed to get the reaction started. This energy is called the activation energy. Activation energy is anything that increases the rate at which the reactants collide (or come together) so that any reaction can occur. Some chemical reactions occur naturally because the activation energy needed to break the bonds of the reactants can be supplied by ambient heat energy. Most reactions cannot, which is a good thing for life. Reasonably unstable molecules such as nucleic acids and proteins would degrade spontaneously if just a small amount of heat energy was needed to overcome the activation energy....
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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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