Kinetic energy is the energy of motion moving objects are working objects

Kinetic energy is the energy of motion moving objects

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Kinetic energy is the energy of motion moving objects are working objects Potential energy is stored energy , the capacity to do work e.g., -water behind a dam -water in a water tower -chemical energy stored in big molecules -an electrochemical gradient across a membrane e.g., gushing water light (moving photons) pulsing molecules flowing ions flowing electrons contracting leg muscles Hoover (Boulder) Dam Cells store potential energy in molecules & in electrochemical gradients
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Potential Energy (PE) Capacity to do work Energy can be converted from one form to another—sitting on top of the slide (PE). Sliding down (KE) Climbing the ladder requires energy input (kinetic energy) against gravity and creates potential energy based on gravity. Sliding down the slide produces kinetic energy: work in progress. In this case the work is heat production by butt friction
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Kinetic Energy Energy of Motion as molecules move to empty space on the other side of the membrane: Energy output Potential Energy = stored energy It has the potential to do work No potential energy No potential to do work Re-establishing the gradient requires energy input. To move molecules against the gradient requires active transport , using the energy stored in ATP A large diffusion gradient represents a high state of potential energy. Lots of potential for molecular motion. Equilibrium This represents a low state of potential energy. No more diffusion gradient. No possibility of kinetic output Diffusion: the energetic view
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Molecules: the energetic view Big Molecules have great potential energy. Electrons are “caged” in the molecules and want to get out. They want to flow. When they escape, they move furiously, producing kinetic energy. Small molecules have little potential energy. Electrons have spent their energy. Anabolic reactions & pathways —These build bigger molecules Energy is required to build polymers and other big molecules Potential energy is stored in polymers and other big molecules Catabolic reactions breakdown polymers and release energy Energy input from ATP Energy out
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THERMODYNAMICS: the mathematical Treatment of Energy 1 st law: Energy can be transformed, but can’t be created or destroyed. --Restated: Energy is constant or conserved, not used up 2 nd law: Every energy transfer or transformation increases disorder --Restated: There is a natural tendency to go from order to disorder. Entropy : a measure of disorder or randomness In biological systems, energy comes from the sun and is converted to chemical energy. For practical purposes, the energy coming in from the sun is eventually lost as heat by biological systems as molecules do their work. The energy in that lost heat continues to exist somewhere in the universe, but after a short while it isn’t of much use to organisms. Low entropy (high order) High entropy (low order)
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If the membrane permits it, diffusion is spontaneous Ordered & Unstable Like water behind the dam, or like a big carbohydrate molecule. Unordered & Stable Like water that’s gone past a dam, or like a collection of CO 2 molecules.
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