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Chapter 8 - Coggle Diagram
Chapter 8
Chemical Reactions & Thermodynamics
Types of Reactions
Exergonic
Spontaneous
Example: Cellular respiration
Releases energy (ΔG < 0)
Endergonic
Requires energy input (ΔG > 0)
Non-spontaneous
Example: Photosynthesis
Thermodynamics
First Law
Energy can't be created/destroyed
Energy transformed
Total energy conserved
Second Law
Entropy (disorder) increases
Some energy lost as heat
Energy transformations are inefficient
Chemical Reactions
Reactants → Products
Bonds broken/formed
Atoms rearranged → new substances
Energy Coupling
Exergonic drives endergonic
ATP hydrolysis powers cell work
Chemical Equilibrium
Definition
Forward rate = Reverse rate
Concentrations constant (not equal)
Reversible Reactions
Double arrows (⇌)
Dynamic state
Equilibrium Constant (Keq)
Keq > 1: Products favored
Keq < 1: Reactants favored
Factors Affecting Equilibrium
Temperature
Pressure (gases)
Concentration
Le Chatelier’s Principle
System shifts to restore balance
Add reactants → shift right
Remove products → shift right
Proteins: Shape & Function
Shape Determines Function
Enzyme active site shape = substrate specific
Misfolded proteins → loss of function
Example: Sickle cell anemia (1 amino acid change)
Denaturation
Heat, pH, salt disrupt structure
Loss of function
Protein Examples
Transport proteins (hemoglobin)
Structural (collagen)
Enzymes (catalysts)
Protein Structure
Secondary: α-helix, β-sheet (H-bonds)
Tertiary: 3D shape (R-group interactions)
Primary: Amino acid sequence
Quaternary: Multiple polypeptides
Metabolic Pathways
Pathway Regulation
Enzymes catalyze each step
Feedback inhibition controls flow
ATP Role
Energy currency
Couples catabolism --> anabolism
Anabolic Pathways
Require energy (endergonic)
Example: Protein synthesis, DNA replication
Build complex molecules
Catabolic Pathways
Release energy (exergonic)
Example: Glycolysis, Krebs cycle
Break down molecules