Bio 132 Exam 4 Objectives

Bio 132 Exam 4 Objectives - 6.1 Define energy emphasizing...

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6.1 Define energy, emphasizing how it is related to work and to heat. Energy is the capacity to do work (expressed in kilojoules, kJ ). Energy can be conveniently measured as heat energy , thermal energy that flows from an object with a higher temperature to an object with a lower temperature; the unit of heat energy is the kilocalorie (kcal), which is equal to 4.184 kilojoules. Heat energy cannot do cell work. 6.3 State the first and second laws of thermodynamics and discuss the implications of these laws as they relate to organisms. A closed system does not exchange energy with its surroundings. Organisms are open systems . The first law of thermodynamics states that energy cannot be created or destroyed but can be transferred and changed in form. The first law explains why organisms cannot produce energy, but as open systems they continuously capture it from the surroundings. The second law of thermodynamics states that disorder (entropy) in the universe, a closed system, is continuously increasing. No energy transfer is 100% efficient; some energy is dissipated as heat , random motion that contributes to entropy or disorder. Organisms maintain their ordered states at the expense of their surroundings. Organisms have a high degree of organization, and appear to refute the second law. However, organisms maintain their degree of order over time only with the constant input of energy from surroundings. The total entropy of the universe always increases over time. 6.5 Distinguish between exergonic and endergonic reactions, and give examples of how they may be coupled. ^G = ^H – T *^S An exergonic reaction has a negative value of ^G; that is, free energy decreases. Such a reaction is spontaneous; it released free energy that can perform work. Free energy increases in an endergonic reaction . Such as reaction has a positive value of ^G, and is nonspontaneous. In a coupled reaction , the input of free energy is required to drive an endergonic reaction is supplied by an exergonic reaction. 6.7 Discuss the central role of ATP in the overall energy metabolism of the cell. ATP is a nucleotide consisting of three main parts: adenine, a nitrogen-containing organic base; ribose, a five carbon sugar; and three phosphate groups, identifiable as phosphorous atoms surrounded by oxygen atoms. ATP is the common link between exergonic and endergonic reactions and between catabolism (degradation of large complex molecules into smaller, simpler molecules) and anabolism (synthesis of complex molecules from simpler molecules.)
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2.8 Distinguish between the terms oxidation and reduction and relate these processes to the transfer of energy. Oxidation
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This test prep was uploaded on 04/07/2008 for the course BIO 132 taught by Professor Lively during the Fall '07 term at Sewanee.

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Bio 132 Exam 4 Objectives - 6.1 Define energy emphasizing...

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