Chapter 8 - Energy, Enzymes and Metabolism Flashcards
Catabolism
Subset of metabolic reactions where molecules are broken down; release of energy from the breakdown into the subunits
Anabolism
Subset of metabolic reactions where simple molecules/smaller units are combined to create complex molecules; requires an input of energy
Metabolism
The sum total of all the chemical reactions occurring in a biological system at a given time
Energy coupling
Energy production reactions of catabolism are used to drive the energy requiring reactions of anabolism; anabolic reactions utilize the stored energy in molecules such as ATP, NADH, NADPH, FADH2; catabolic reactions release energy that is then stored in molecules such as ADP, NAD+, NADP+ and FAD
Energy
Capacity to do work or the capacity for change
Potential Energy
Energy stored as chemical bonds, concentration gradients or electric charge imbalances
Kinetic Energy
The energy of movement
First law of thermodynamics
Law of conservation of energy; energy of the universe is constant; energy cannot be created or destroyed, energy can only be transformed from one type to another
Second law of thermodynamics
All energy transfers or transformations make the universe more disordered (increases entropy); no energy transformation is 100% efficient, some energy is lost to disorder; overall, the universe increases disorder
Gibbs Free Energy, G
The portion of a system’s energy that is able to perform work when T (temperature) is uniform throughout a system; change in G is a measure of instability of a system, high G = unstable
Spontaneous reaction
Can occur without assistance; reaction will move forward without assistance; increases the stability of a system; -G
Non-spontaneous reaction
Can only occur if energy is added; reaction cannot move forward without outside intervention; decreases the stability of a system; +G
Exergonic/Exothermic reactions
Catabolic reactions; net release of free energy; -G; spontaneous; stability of system increases; reactants have more energy than products
Endergonic/Endothermic reactions
Anabolic reactions; requires energy from its environment; +G; non-spontaneous; stability of system decreases; reactants have less energy than products
ATP
Adenosine triphosphate; the source of energy for cellular work; can hold and transfer free energy
ATP hydrolysis
Exergonic reaction that involves the breakdown of ATP and a release of free energy; ATP releases a large amount of energy when it undergoes phosphorylation: donates a terminal phosphate group to another molecule to activate the molecule; yields G: -7.3 kcal/mol under standard conditions