Life, Cells, and Thermodynamics Chapter 1 Life, Cells, and Thermodynamics

Life, Cells, and Thermodynamics Chapter 1 Life, Cells, and Thermodynamics Key Concepts 1.1: • Biological molecules are constructed from a limited number of elements. • Certain functional groups and linkages characterize different types of biomolecules. • During chemical evolution, simple compounds condensed to form more complex molecules and polymers. • Self-replicating molecules would have been subject to natural selection.

Living Matter Consists of Few Elements

Filamentous Bacterial Cell Microfossil

Hydrothermal Vent

Carboxylic Acid-Amine Reactions

Complementary Molecules Associate

Biochemistry Functional Groups and Linkages

Biochemistry Functional Groups and Linkages

Biological Polymers

Intramolecular Complementary & Replication

Cellular Architecture Chapter 1 Cellular Architecture Key Concepts 1.2: • Compartmentation of cells promotes efficiency by maintaining high local concentrations of reactants. • Metabolic pathways evolved to synthesize molecules and generate energy. • The simplest cells are prokaryotes. • Eukaryotes are characterized by numerous membrane-bounded organelles, including a nucleus. • The phylogenetic tree of life includes three domains: bacteria, archaea, and eukarya. • Evolution occurs as natural selection acts on randomly occurring variations among individuals.

Cross-section of E. coli

Relative Prokaryotic Cell Size

Typical Animal Cell

Phylogenetic Relationship of 3 Domains

Chapter 1 Thermodynamics Key Concepts 1.3: • Energy must be conserved, but it can take different forms. • In most biochemical systems, enthalpy is equivalent to heat. • Entropy, a measure of a system’s disorder, tends to increase. • The free energy change for a process is determined by the change in enthalpy and the change in entropy. • A spontaneous process occurs with a decrease in free energy. • The free energy change for a reaction can be calculated from the temperature and the concentrations and stoichiometry of the reactants and products. • Biochemists define standard state conditions as a temperature of 25°C, a pressure of 1 atm, and a pH of 7.0. • Organisms are nonequilibrium, open systems that constantly exchange matter and energy with their surroundings. • Enzymes increase the rates of thermodynamically favorable reactions.

Entropy Increases

Spontaneity Depends on Enthalpy & Entropy

Energy Flow in an Open System Biosphere: Energy Flow in an Open System

Chapter 1 Thermodynamics Checkpoints • Summarize the relationship between energy (U), heat (q), and work (w). • Restate the first and second laws of thermodynamics. • Use the analogy of a china cabinet to describe a system with low entropy or high entropy. • Explain why changes in both enthalpy (ΔH) and entropy (ΔS) determine the spontaneity of a process.

Chapter 1 Thermodynamics Checkpoint s: • What is the free energy change for a reaction at equilibrium? • Write the equation showing the relationship between ΔG° and Keq. • Write the equation showing the relationship between ΔG, ΔG°, and the concentrations of the reactants and products. • Explain how biochemists define the standard state of a solute. Why do biochemists and chemists use different conventions? • Explain how organisms avoid reaching equilibrium while maintaining a steady state. • How do enzymes affect the rate and free energy change of a reaction?