BY 123 Exam II Notes - Figure 9.1 All energy comes from the...

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- Figure 9.1 - All energy comes from the sun. - Chemotrophs do not use the sun. - Less than 1% of all the energy that comes to Earth from the sun is used for photosynthesis - Chloroplast take in sun energy, the energy is stored as glucose, then the cells mitochondria break it down. - Bio-energetics- energy relating to living organisms - Energy is the capacity to do work or cause change. - Metabolism is the totality of an organism’s chemical processes(managing energy and material) - Anabolic pathways – use energy and build complex molecules( pathways to make proteins, polysaccharides, etc./photosynthesis make sugar from O2 and H2O) *these are primarily dehydration/condensation reactions - Catabolic pathways – release energy by breaking down complex molecules into simpler molecules(respiration sugars, etc., are broken down to CO2 and H2O, releasing energy) *these are largely hydrolysis reactions - Kinetic energy vs. potential energy o Kinetic energy- energy of motion. o Potential energy- stored energy capable of doing work. o When chemical reactions take place potential energy is converted to kinetic energy. - Thermodynamics- The study of energy transformation in matter. - 1 st Law of Thermodynamics- energy cannot be created or destroyed, but it can be transformed from one form to another or transferred. o Oxidize carbohydrates to make ATP o This is also known as the Principle of Conservation of energy. - Organisms release heat - The amount of free energy is declining. - A closed system has no transfer of energy. - Nature moves toward disorder o The measure of disorder is entropy. - 2 nd Law of Thermodynamics- Every energy transfer or transformation makes the universe more disordered (increasing entropy=disorder or randomness). Heat= most disordered form of energy. - The energy throughout the universe is constant; it’s the quality (order) that is decreasing. - Entropy of universe is increasing* - (Fig. 8.7, pg. 147) - The entropy of a system can decrease as long as the entropy of the universe increases. - Bond energy’s are defined as the net energy consumed to break bonds of reactants and energy released from products. - Spontaneous reactions don’t require external energy to be added. - The more unstable a substance is the more energy it has. - Unstable systems want to become stable. - Free energy can be used to do work. - Free energy (G) is the portion of a system that is available to perform work. - ΔG change in free energy during a process or step - 2 nd Law ΔG of universe overall has to decrease in each step of a pathway - In spontaneous systems the free energy of the system decrease and the stability increases.
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o The reason for this is that in spontaneous system the substances stabilize themselves spontaneously. This in turn reduces the amount of free energy, because it is being used to stabilize the substance. -
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BY 123 Exam II Notes - Figure 9.1 All energy comes from the...

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