BIOLOGY 151 Chapter Notes - Chapter 7: Light-Dependent Reactions, Negative Number, Activation Energy
13 Jun 2018
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ENERGY AND METABOLISM
● BIOENERGETICS: to describe the concept of energy flow through living systems such
as cells
● METABOLISM: all of the chemical reactions that take place inside cells, including those
that consume or generate energy
METABOLISM PATHWAYS
● During the light reactions of photosynthesis, energy is provided by a molecule called
ATP
● ANABOLIC pathways: requires energy; building polymers
● CATABOLIC pathways: producing energy; breaking down polymers into their
monomers
ENERGY
● THERMODYNAMICS: study of energy and energy transfer involving physical matter
● OPEN SYSTEM: energy can be exchanged with its surroundings
● CLOSED SYSTEM: cannot exchange energy with its surroundings
○ Biological organisms are open systems
THERMODYNAMICS
● First law states that the total amount of energy in the universe is constant and conserved.
● Ex. gas stoves transform chemical energy from natural gas into heat energy
● HEAT ENERGY: the energy transferred from one system to another that isn’t work
○ Ex. when a light bulb is turned on, some of the energy being converted from
electrical energy into light energy is lost as heat energy
POTENTIAL AND KINETIC ENERGY
● KINETIC ENERGY: energy associated with objects in motion
● POTENTIAL ENERGY: could be transformed into kinetic energy until all of the PE was
exhausted
○ Ex. the energy of water held behind a dam or a person about to skydive out of an
airplane
○ It’s associated with the location of matter and the structure of matter
○ The bonds that hold the atoms of molecules together exist in a particular structure
that has PE
FREE AND ACTIVATION ENERGY
● A measurement of free energy is used to quantify these energy transfers
● Free energy refers to energy associated with a chemical reaction that’s available after the
losses are accounted for; it’s basically usable energy
● If energy is released during a chemical reaction, then the change in free energy is (delta
G) with a negative number
○ A negative change in free energy also means that products of the reaction have
less free energy than the reactants because they release some free energy guring
the reaction
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Document Summary
Bioenergetics: to describe the concept of energy flow through living systems such as cells. Metabolism: all of the chemical reactions that take place inside cells, including those that consume or generate energy. During the light reactions of photosynthesis, energy is provided by a molecule called. Catabolic pathways: producing energy; breaking down polymers into their monomers. Thermodynamics: study of energy and energy transfer involving physical matter. Open system: energy can be exchanged with its surroundings. Closed system: cannot exchange energy with its surroundings. First law states that the total amount of energy in the universe is constant and conserved. Ex. gas stoves transform chemical energy from natural gas into heat energy. Heat energy: the energy transferred from one system to another that isn"t work. Ex. when a light bulb is turned on, some of the energy being converted from electrical energy into light energy is lost as heat energy. Kinetic energy: energy associated with objects in motion.
