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An Introduction to Metabolism - Coggle Diagram
An Introduction to Metabolism
An Organism's Metabolism
Forms of Energy
Thermal energy- heat being transferred from one object to another
Ex. powering photosynthesis in green plants
Potential energy - matter possesses because of its location or structure
ex. water behind a dam
kinetic energy - relative motion of objects
Ex. the contraction of leg muscles pushed bicycle pedals
Chemical energy - energy available in molecules for release in a chemical reaction; a form of potential energy
Metabolic Pathway
A specific molecule is altered in a series of defined steps, resulting in a certain product
The mechanism that regulates these balances metabolic supply and demand
Catabolic Pathways
Releases energy by breaking down complex molecules to simpler molecules
Ex. Cellular respiration, which breaks down glucose and other organic fuels in the presence of oxygen to carbon dioxide and water
Anabolic pathways
Consumes energy to synthesize a complex molecule from simpler molecules
Ex. synthesis of an amino acid and protein from amino acid
Metabolism - the totality of an organism's chemical reactions
Bioenergetic - the study of how energy flows through living organisms
The Laws of Energy Transformation
First law of thermodynamics
Energy can be transferred and transformed but it cannot be created or destroyed
Thermodynamics - the study of the energy transformation that occur in collection of matter
Second law of thermodynamics
Every energy transfer or transformation increases the entropy of the universe
Spontaneous process - a process that occurs without an overall input of energy
The Free Energy Change of a Reaction
Free energy- a portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system, as a living cell
Gibbs free energy- represents the energy available to do work in a system, ΔG = ΔH - TΔS
Exergonic v. Endergonic reactions - Exergonic reactions release energy and occur spontaneously (ΔG < 0), while endergonic reactions require energy input and are non-spontaneous (ΔG > 0)
Exergonic reaction -A spontaneous chemical reaction in which there is a net release of free energy
Endergonic reaction - absorbs free energy from its surroundings
Spontaneity and stability - A negative ΔG indicates a spontaneous reaction, meaning the system loses free energy and becomes more stable. Systems naturally progress towards lower free energy states, enhancing stability.
ATP Powers Cellular Work
Energy coupling- the use of an exergonic process to drive an endergonic one. ATP is responsible for mediating most energy coupling in cells
ATP contains sugar ribose, with the nitrogenous base adenine and a chain of three phosphate groups
Phosphorylated intermediate - A molecule with a phosphate group covalently bound to it, making it more reactive (less stable) than the unphosphorylated molecule
Regeneration of ATP
is a crucial process in cellular metabolism where ATP, a primary energy carrier, is continuously replenished. ATP is regenerated by adding a phosphate group to ADP, using energy from catabolic reactions. This cycle is vital for maintaining energy balance in cells, enabling them to perform various functions
Enzymes Speed Up Metabolic Reactions
Activation energy- the amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activation
Substrate -the reactant on which an enzyme works
Enzyme-substrate complex - temporary complex formed when an enzyme binds to its substrate molecule
Induced fit - caused by entry of the substrate, the change in shape of the active site of an enzyme so that it binds more snugly to the substrate
Cofactors- any nonprotein molecule or ion that is required for the proper functioning of an enzyme. Cofactors can be permanently bound to the active site or may bind loosely and reversibly, along with the substrate, during catalysis
Coenzyme - an organic molecule serving as a cofactor
Competitive inhibitors - a substance that reduces the activity of an enzyme by entering the active site in place of the substrate, whose structure it mimic
Noncompetitive inhibitors - a substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing the enzyme’s shape so that the active site no longer effectively catalyzes the conversion of substrate to product
