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Ch 8. An Introduction to Metabolism - Coggle Diagram
Ch 8. An Introduction to Metabolism
Metabolic Pathway
A specific molecule is altered in a series of steps to produce a product
Each step is catalyzed by a specific enzyme (a macromolecule that speeds up a specific reaction)
Types of Metabolic Pathways
Catabolic Pathways
Release energy by breaking down complex molecules into simpler compounds
Example: Cellular respiration – breakdown of glucose in the presence of O₂
Anabolic Pathways
Consume energy to build complex molecules from simpler ones
example: Synthesis of proteins from amino acids
Forms of Energy
Kinetic Energy
energy of motion (e.g., water turning turbines)
Thermal Energy
random motion of atoms; transfer = heat
Light Energy
used to do work (e.g., photosynthesis)
Potential Energy
tored energy from position or structure (e.g., water behind dam)
Thermodynamics
Study of energy transformations
Isolated system – no exchange of energy or matter
Open system – energy and matter can transfer (organisms are open systems)
First Law of Thermodynamics
Energy of the universe is constant
Energy can be transferred or transformed, not created or destroyed
Also called Law of Conservation of Energy
Second Law of Thermodynamics
Every energy transfer increases entropy (disorder) of the universe
Some energy is lost as heat and becomes unavailable for work
Entropy = measure of molecular disorder or randomness
Free Energy and Spontaneis
Portion of a system’s energy that can do work
Measures a system’s stability
Systems with high free energy = unstable