Chapter_6_Metabolism
6.1 Energy and Metabolism
Key Concepts
Bioenergetics: Study of energy flow in living systems.
Metabolism: All chemical reactions within a cell or organism.
Metabolic Pathways: Series of reactions transforming substrates into final products (e.g., photosynthesis and cellular respiration).
Types of Reactions
Anabolic Pathways: Require energy to synthesize larger molecules.
Catabolic Pathways: Release energy by breaking down larger molecules.
Evolution of Metabolic Pathways
Shared pathways among life forms support the theory of evolution from common ancestors.
6.2 Potential, Kinetic, Free, and Activation Energy
Definitions
Energy: Ability to do work; two types:
Kinetic Energy: Energy of motion.
Potential Energy: Stored energy (e.g., in chemical bonds).
Gibbs Free Energy (G): Usable energy in a system; changes during reactions denoted as ΔG.
Exergonic Reactions: Release energy (ΔG is negative).
Endergonic Reactions: Require energy input (ΔG is positive).
Activation Energy
Required to initiate a chemical reaction by reaching a transition state. Lower in catalyzed reactions.
6.3 The Laws of Thermodynamics
Key Laws
First Law: Energy cannot be created or destroyed, only transformed.
Second Law: Energy transfer is inefficient; results in increased entropy (disorder).
6.4 ATP: Adenosine Triphosphate
ATP Structure
Composed of adenosine and three high-energy phosphate groups.
Function
ATP serves as the primary energy currency in cells.
ATP hydrolysis to ADP releases energy, driving endergonic reactions.
6.5 Enzymes
Role in Metabolism
Enzymes: Protein catalysts that lower activation energy, speeding up reactions.
Specific to particular reactions due to their unique 3D shapes and active sites.
Enzyme Mechanisms
Induced Fit Model: Enzyme changes shape to optimize binding and catalysis.
Regulation of Enzymes
Factors affecting enzyme activity: temperature, pH, coenzymes, and inhibitors (competitive vs. noncompetitive).
Feedback Inhibition: End product of a pathway inhibits an upstream enzyme, regulating metabolic pathways.
Chapter_6_Metabolism
6.1 Energy and Metabolism
Key Concepts
Bioenergetics: Study of energy flow in living systems.
Metabolism: All chemical reactions within a cell or organism.
Metabolic Pathways: Series of reactions transforming substrates into final products (e.g., photosynthesis and cellular respiration).
Types of Reactions
Anabolic Pathways: Require energy to synthesize larger molecules.
Catabolic Pathways: Release energy by breaking down larger molecules.
Evolution of Metabolic Pathways
Shared pathways among life forms support the theory of evolution from common ancestors.
6.2 Potential, Kinetic, Free, and Activation Energy
Definitions
Energy: Ability to do work; two types:
Kinetic Energy: Energy of motion.
Potential Energy: Stored energy (e.g., in chemical bonds).
Gibbs Free Energy (G): Usable energy in a system; changes during reactions denoted as ΔG.
Exergonic Reactions: Release energy (ΔG is negative).
Endergonic Reactions: Require energy input (ΔG is positive).
Activation Energy
Required to initiate a chemical reaction by reaching a transition state. Lower in catalyzed reactions.
6.3 The Laws of Thermodynamics
Key Laws
First Law: Energy cannot be created or destroyed, only transformed.
Second Law: Energy transfer is inefficient; results in increased entropy (disorder).
6.4 ATP: Adenosine Triphosphate
ATP Structure
Composed of adenosine and three high-energy phosphate groups.
Function
ATP serves as the primary energy currency in cells.
ATP hydrolysis to ADP releases energy, driving endergonic reactions.
6.5 Enzymes
Role in Metabolism
Enzymes: Protein catalysts that lower activation energy, speeding up reactions.
Specific to particular reactions due to their unique 3D shapes and active sites.
Enzyme Mechanisms
Induced Fit Model: Enzyme changes shape to optimize binding and catalysis.
Regulation of Enzymes
Factors affecting enzyme activity: temperature, pH, coenzymes, and inhibitors (competitive vs. noncompetitive).
Feedback Inhibition: End product of a pathway inhibits an upstream enzyme, regulating metabolic pathways.
