week 5 energy intor

Energy Types

• Potential Energy

  • Energy stored in chemical bonds.

  • Example: Accumulation of water behind a dam represents potential energy.

• Kinetic Energy

  • Energy in motion or action.

  • Example: Movement of electrons in an electric current.

  • Analogy: Flow of water in a river (water movement as kinetic energy).

  • Conversion: Potential energy converts to kinetic energy when water flows from a dam.

• Units of Energy

  • The standard unit is the joule.

  • Energy exists in many forms including:

    • Chemical Energy: Energy available when chemical bonds are broken or formed.

    • Electrical Energy: Kinetic energy of flowing electrons.

    • Mechanical Energy: Associated with movement or position of an object.

• Energy Conversion

  • Potential energy can be converted to kinetic energy and vice versa.

  • Kinetic energy can also convert to electric or mechanical energy.

Thermodynamics

• First Law of Thermodynamics

  • Law of conservation of energy: Energy cannot be created or destroyed; it can only change forms.

• Second Law of Thermodynamics

  • Free energy decreases while unusable energy (entropy) increases over time.

  • Energy conversions are not perfectly efficient; some energy converts to unusable forms.

Gibbs Free Energy

• Defines energy transformations in biological systems.

• Gibbs Free Energy Formula:

  • G = H - TS

  • Where:

    • G = Free energy

    • H = Enthalpy (total energy)

    • T = Absolute temperature

    • S = Entropy (unusable energy).

• Changes in free energy (ΔG) denote energy shifts in reactions between reactants and products.

  • ΔG = ΔH - TΔS

Types of Chemical Reactions

• Exergonic Reactions

  • Free energy of products < Free energy of reactants.

  • Negative ΔG indicates energy release to the surroundings.

  • Example: Oxidation of glucose to CO2 and H2O.

• Endergonic Reactions

  • Free energy of products > Free energy of reactants.

  • Positive ΔG indicates energy absorption from the surroundings.

  • Example: Formation of peptides from amino acids (peptide bonds).

Analogy & Equilibrium

• Analogy of Energy Reactions

  • Exergonic reactions likened to a ball rolling downhill.

  • Endergonic reactions likened to pushing a ball uphill (requires energy).

• Equilibrium Constant (Keq)

  • The ratio of product concentrations to reactant concentrations at equilibrium.

  • Free energy changes in reactions depend on Keq.

• At equilibrium, changes in free energy expressed as joules per mole.

The product of ATP hydrolysis is a. ADP. When ATP is hydrolyzed, it loses one phosphate group to form adenosine diphosphate (ADP) and releases energy.