Chapter 3 Bioenergetics

Chapter 3 Bioenergetics - CHAPTER 3 BIOENERGETICS, ENZYMES,...

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C HAPTER  3  B IOENERGETICS , E NZYMES , A ND  M ETABOLISM (BIO201 M ATERIAL   IN  B LUE ,   BIO211  MATERIAL   IN  R ED MATERIAL   REQUIRED   FOR   NEITHER   COURSE   IN   BLACK I   CAN T   CONTROL   THE   COLOR   OF   ILLUSTRATIONS ). T HIS   OUTLINE   WAS   MADE   FROM   AN   EARLIER   VERSION   OF   YOUR   TEXT   AND   MAY   NOT   CORRESPOND   EXACTLY Bioenergetics: Definitions I. Bioenergetics – the study of the various types of energy transformations that occur in living organisms; to maintain its high level of activity, a cell must acquire & expend energy II. Energy - capacity to do work (the capacity to change or move something) A. Energy exists in two alternate states 1. Potential energy - energy of object by virtue of its position; rock perched on edge of cliff; has potential to do work since it exists in a field of force (a gravitational field) 2. Kinetic energy - energy of motion; push rock over cliff edge -> falls (can perform work); e. g., directed Na + ion movement into cell is kinetic energy; can be used to do work (nerve impulse) B. Two factors must be considered when you are involved in the measurement of energy at work 1. Potential factor - proportional to the intensity of the field of force (distance rock will fall; for the movement of charged ions, potential factor is voltage) 2. Capacity factor - provides some measure of the "size" of the subject being considered (rock’s mass; for the movement of charged ions, capacity factor is combined charge of particles) III. Work (energy released during such events) - multiple of potential & capacity factors; as either one increases so too does the amount of energy The Laws of Thermodynamics and the Concept of Entropy I. Thermodynamics - study of the changes in energy that accompany events in the Universe A. Use it to predict direction events take & whether or not energy input is needed for them to happen B. Gives no help in defining how rapidly specific process occurs or specific mechanism cell uses to do it II. The First Law of Thermodynamics - energy can be neither created nor destroyed (Law of Conservation of Energy); total energy in Universe remains constant (regardless of transduction process) A. Energy can, however, be transduced - burning fuel, polysaccharide breakdown, photosynthesis 1. Several organism communities are independent of photosynthesis – communities residing in hydrothermal vents on ocean floor; depends on energy obtained by bacterial chemosynthesis 2. Some animals (fireflies, luminous fish) convert chemical energy back into light
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B. Universe divided into 2 parts to discuss energy transformations involving matter - system under study (certain space in Universe or amount of matter, e.g., living cell) & surroundings (rest of Universe) 1. Usually stipulate that system does not exchange matter with environment, but may exchange energy with surroundings - closed system C. Change in a system's energy during an event is manifested by a change in system heat
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Chapter 3 Bioenergetics - CHAPTER 3 BIOENERGETICS, ENZYMES,...

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