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Introduction to Metabolism - Coggle Diagram
Introduction to Metabolism
8.1
Metabolism
Definition: The totality of an organisms chemical reactions.
Metabolic Pathway
Definition: Series of chemical reactions that either build complex molecules or break complex molecules into smaller molecules.
Catabolic Pathways
Breakdown complex molecules.
Ex. Cellular respiration.
Anabolic Pathways
Build complex molecules.
Ex. Synthesis of amino acids, dehydration synthesis.
Energy
Bioenergetics
Definition: The study of how energy flows through living organisms.
Definition: The capacity to cause change.
Forms of Energy
Kinetic Energy
Definition: Energy associated with the relative motion of objects. (Moving)
Thermal Energy
Definition: Kinetic energy associated with with the random movement of atoms or molecules. The transfer of energy in thermal energy is called heat.
Potential Energy
Definition: Energy that matter possesses because of it location or structure. (Stationary)
Chemical Energy
Definition: Energy released during chemical reactions.
Thermodynamics
Definition: The study of the energy transformations that occur in a collection.
First Law of Thermodynamics
Definition: Energy can be transferred and transformed but cannot be created or destroyed.
Entropy
The measure of randomness.
Second Law of Thermodynamics
Definition: Every energy transfer of transformation increases the entropy of the universe.
Spontaneous Process
Occurs without energy input, can happen quickly or slowly. Leads to an increase of entropy.
8.5
Allosteric Regulation
Definition: Term used to describe any case in which a proteins function at one site is affected by the binding of a regulatory molecule to a separate site.
The binding of an activator to a regulatory site stabilizes the shape that has functional active sites, whereas the binding of an inhibitor stabilizes the inactive form of the enzyme.
Cooperativity
Definition: Mechanism that amplifies the response of enzymes to substrates.
Feedback Inhibition
A mode of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.
8.2
Free Energy
Definition: Energy that can work when temperature and pressure are uniform through the system.
Free energy can be calculated for a chemical reaction with the equation.
Higher (G) = unstable, lower (G) = more stable.
(G) is negative for ALL spontaneous processes and is zero or negative for ALL non-spontaneous processes.
In spontaneous processes free energy is lost.
Reactions
Exergonic Reactions
Definition: Proceeds with a net release of free energy to the surroundings. "Energy outward"
All -(G) spontaneous reactions are exergonic. They have more reactants than products.
Endergonic Reactions
Definition: Absorbs free energy from the surroundings. "Energy inward"
All +(G) reactions are endergonic and have more products than reactants.
8.3
Chemical Work
Definition: The pushing of endergonic reactions that would not occur spontaneously.
Transport Work
Definition: The pumping of substances across membranes of substances across membranes against the direction of spontaneous movement.
Mechanical Work
The contraction of muscle cells and the movement of chromosomes during cellular reproduction.
Breaking bonds during a chemical reaction does not release energy it requires energy.
Energy Coupling
Definition: The use of an exergonic process to drive an endergonic one.
ATP (Adenosine Triphosphate)
Contains sugar ribose, with the nitrogenous base adenine and a chain of three phosphate groups.
Bonds between the phosphate groups of ATP can be broken by hydrolysis.
ATP is a renewable resource that can be regenerated by the addition of phosphate to ADP.
8.4
Activation Energy
The amount of energy that reactants must absorb before a chemical reaction will start.
Catalysis
A process by which a chemical agent called a catalyst selectively increases the rate of a reaction without being consumed by the reaction.
Substrate
The reactant an enzyme acts on.
Active Site
The specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs.
Cofactors
Any nonprotein molecule or ion that is required for the proper functioning of an enzyme.
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.
Inhibitors
Competitive Inhibitors
A substance that reduces the activity of an enzyme by entering the active site in place of the substrate, whose structure it mimics.
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.
